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2021-06-29Merge tag 'x86-entry-2021-06-29' of ↵Linus Torvalds1-26/+61
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 entry code related updates from Thomas Gleixner: - Consolidate the macros for .byte ... opcode sequences - Deduplicate register offset defines in include files - Simplify the ia32,x32 compat handling of the related syscall tables to get rid of #ifdeffery. - Clear all EFLAGS which are not required for syscall handling - Consolidate the syscall tables and switch the generation over to the generic shell script and remove the CFLAGS tweaks which are not longer required. - Use 'int' type for system call numbers to match the generic code. - Add more selftests for syscalls * tag 'x86-entry-2021-06-29' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/syscalls: Don't adjust CFLAGS for syscall tables x86/syscalls: Remove -Wno-override-init for syscall tables x86/uml/syscalls: Remove array index from syscall initializers x86/syscalls: Clear 'offset' and 'prefix' in case they are set in env x86/entry: Use int everywhere for system call numbers x86/entry: Treat out of range and gap system calls the same x86/entry/64: Sign-extend system calls on entry to int selftests/x86/syscall: Add tests under ptrace to syscall_numbering_64 selftests/x86/syscall: Simplify message reporting in syscall_numbering selftests/x86/syscall: Update and extend syscall_numbering_64 x86/syscalls: Switch to generic syscallhdr.sh x86/syscalls: Use __NR_syscalls instead of __NR_syscall_max x86/unistd: Define X32_NR_syscalls only for 64-bit kernel x86/syscalls: Stop filling syscall arrays with *_sys_ni_syscall x86/syscalls: Switch to generic syscalltbl.sh x86/entry/x32: Rename __x32_compat_sys_* to __x64_compat_sys_*
2021-06-28Merge tag 'x86-asm-2021-06-28' of ↵Linus Torvalds1-1/+1
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 asm updates from Ingo Molnar: - Micro-optimize and standardize the do_syscall_64() calling convention - Make syscall entry flags clearing more conservative - Clean up syscall table handling - Clean up & standardize assembly macros, in preparation of FRED - Misc cleanups and fixes * tag 'x86-asm-2021-06-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/asm: Make <asm/asm.h> valid on cross-builds as well x86/regs: Syscall_get_nr() returns -1 for a non-system call x86/entry: Split PUSH_AND_CLEAR_REGS into two submacros x86/syscall: Maximize MSR_SYSCALL_MASK x86/syscall: Unconditionally prototype {ia32,x32}_sys_call_table[] x86/entry: Reverse arguments to do_syscall_64() x86/entry: Unify definitions from <asm/calling.h> and <asm/ptrace-abi.h> x86/asm: Use _ASM_BYTES() in <asm/nops.h> x86/asm: Add _ASM_BYTES() macro for a .byte ... opcode sequence x86/asm: Have the __ASM_FORM macros handle commas in arguments
2021-06-22x86/xen: Fix noinstr fail in xen_pv_evtchn_do_upcall()Peter Zijlstra1-1/+2
Fix: vmlinux.o: warning: objtool: xen_pv_evtchn_do_upcall()+0x23: call to irq_enter_rcu() leaves .noinstr.text section Fixes: 359f01d1816f ("x86/entry: Use run_sysvec_on_irqstack_cond() for XEN upcall") Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/20210621120120.532960208@infradead.org
2021-06-22x86/entry: Fix noinstr fail in __do_fast_syscall_32()Peter Zijlstra1-1/+1
Fix: vmlinux.o: warning: objtool: __do_fast_syscall_32()+0xf5: call to trace_hardirqs_off() leaves .noinstr.text section Fixes: 5d5675df792f ("x86/entry: Fix entry/exit mismatch on failed fast 32-bit syscalls") Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/20210621120120.467898710@infradead.org
2021-05-25x86/entry: Use int everywhere for system call numbersH. Peter Anvin (Intel)1-28/+59
System call numbers are defined as int, so use int everywhere for system call numbers. This is strictly a cleanup; it should not change anything user visible; all ABI changes have been done in the preceeding patches. [ tglx: Replaced the unsigned long cast ] Signed-off-by: H. Peter Anvin (Intel) <hpa@zytor.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20210518191303.4135296-7-hpa@zytor.com
2021-05-20x86/entry: Treat out of range and gap system calls the sameH. Peter Anvin (Intel)1-0/+4
The current 64-bit system call entry code treats out-of-range system calls differently than system calls that map to a hole in the system call table. This is visible to the user if system calls are intercepted via ptrace or seccomp and the return value (regs->ax) is modified: in the former case, the return value is preserved, and in the latter case, sys_ni_syscall() is called and the return value is forced to -ENOSYS. The API spec in <asm-generic/syscalls.h> is very clear that only (int)-1 is the non-system-call sentinel value, so make the system call behavior consistent by calling sys_ni_syscall() for all invalid system call numbers except for -1. Although currently sys_ni_syscall() simply returns -ENOSYS, calling it explicitly is friendly for tracing and future possible extensions, and as this is an error path there is no reason to optimize it. Signed-off-by: H. Peter Anvin (Intel) <hpa@zytor.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20210518191303.4135296-6-hpa@zytor.com
2021-05-12x86/entry: Reverse arguments to do_syscall_64()H. Peter Anvin (Intel)1-1/+1
Reverse the order of arguments to do_syscall_64() so that the first argument is the pt_regs pointer. This is not only consistent with *all* other entry points from assembly, but it actually makes the compiled code slightly better. Signed-off-by: H. Peter Anvin (Intel) <hpa@zytor.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/20210510185316.3307264-3-hpa@zytor.com
2021-04-08x86/entry: Enable random_kstack_offset supportKees Cook1-0/+3
Allow for a randomized stack offset on a per-syscall basis, with roughly 5-6 bits of entropy, depending on compiler and word size. Since the method of offsetting uses macros, this cannot live in the common entry code (the stack offset needs to be retained for the life of the syscall, which means it needs to happen at the actual entry point). Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20210401232347.2791257-5-keescook@chromium.org
2021-03-06x86/entry: Fix entry/exit mismatch on failed fast 32-bit syscallsAndy Lutomirski1-1/+2
On a 32-bit fast syscall that fails to read its arguments from user memory, the kernel currently does syscall exit work but not syscall entry work. This confuses audit and ptrace. For example: $ ./tools/testing/selftests/x86/syscall_arg_fault_32 ... strace: pid 264258: entering, ptrace_syscall_info.op == 2 ... This is a minimal fix intended for ease of backporting. A more complete cleanup is coming. Fixes: 0b085e68f407 ("x86/entry: Consolidate 32/64 bit syscall entry") Signed-off-by: Andy Lutomirski <luto@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Borislav Petkov <bp@suse.de> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/8c82296ddf803b91f8d1e5eac89e5803ba54ab0e.1614884673.git.luto@kernel.org
2021-02-12Merge branch 'x86/paravirt' into x86/entryIngo Molnar1-3/+7
Merge in the recent paravirt changes to resolve conflicts caused by objtool annotations. Conflicts: arch/x86/xen/xen-asm.S Signed-off-by: Ingo Molnar <mingo@kernel.org>
2021-02-11x86/entry: Use run_sysvec_on_irqstack_cond() for XEN upcallThomas Gleixner1-13/+6
To avoid yet another macro implementation reuse the existing run_sysvec_on_irqstack_cond() and move the set_irq_regs() handling into the called function. Makes the code even simpler. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20210210002512.869753106@linutronix.de
2021-02-11x86/entry: Fix instrumentation annotationThomas Gleixner1-1/+1
Embracing a callout into instrumentation_begin() / instrumentation_begin() does not really make sense. Make the latter instrumentation_end(). Fixes: 2f6474e4636b ("x86/entry: Switch XEN/PV hypercall entry to IDTENTRY") Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Kees Cook <keescook@chromium.org> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20210210002512.106502464@linutronix.de
2021-01-12x86/entry: Fix noinstr failPeter Zijlstra1-3/+7
vmlinux.o: warning: objtool: __do_fast_syscall_32()+0x47: call to syscall_enter_from_user_mode_work() leaves .noinstr.text section Fixes: 4facb95b7ada ("x86/entry: Unbreak 32bit fast syscall") Reported-by: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20210106144017.472696632@infradead.org
2020-11-05x86/entry: Move nmi entry/exit into common codeThomas Gleixner1-34/+0
Lockdep state handling on NMI enter and exit is nothing specific to X86. It's not any different on other architectures. Also the extra state type is not necessary, irqentry_state_t can carry the necessary information as well. Move it to common code and extend irqentry_state_t to carry lockdep state. [ Ira: Make exit_rcu and lockdep a union as they are mutually exclusive between the IRQ and NMI exceptions, and add kernel documentation for struct irqentry_state_t ] Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ira Weiny <ira.weiny@intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20201102205320.1458656-7-ira.weiny@intel.com
2020-09-22x86/irq: Make run_on_irqstack_cond() typesafeThomas Gleixner1-1/+1
Sami reported that run_on_irqstack_cond() requires the caller to cast functions to mismatching types, which trips indirect call Control-Flow Integrity (CFI) in Clang. Instead of disabling CFI on that function, provide proper helpers for the three call variants. The actual ASM code stays the same as that is out of reach. [ bp: Fix __run_on_irqstack() prototype to match. ] Fixes: 931b94145981 ("x86/entry: Provide helpers for executing on the irqstack") Reported-by: Nathan Chancellor <natechancellor@gmail.com> Reported-by: Sami Tolvanen <samitolvanen@google.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Borislav Petkov <bp@suse.de> Tested-by: Sami Tolvanen <samitolvanen@google.com> Cc: <stable@vger.kernel.org> Link: https://github.com/ClangBuiltLinux/linux/issues/1052 Link: https://lkml.kernel.org/r/87pn6eb5tv.fsf@nanos.tec.linutronix.de
2020-09-04x86/entry: Unbreak 32bit fast syscallThomas Gleixner1-9/+20
Andy reported that the syscall treacing for 32bit fast syscall fails: # ./tools/testing/selftests/x86/ptrace_syscall_32 ... [RUN] SYSEMU [FAIL] Initial args are wrong (nr=224, args=10 11 12 13 14 4289172732) ... [RUN] SYSCALL [FAIL] Initial args are wrong (nr=29, args=0 0 0 0 0 4289172732) The eason is that the conversion to generic entry code moved the retrieval of the sixth argument (EBP) after the point where the syscall entry work runs, i.e. ptrace, seccomp, audit... Unbreak it by providing a split up version of syscall_enter_from_user_mode(). - syscall_enter_from_user_mode_prepare() establishes state and enables interrupts - syscall_enter_from_user_mode_work() runs the entry work Replace the call to syscall_enter_from_user_mode() in the 32bit fast syscall C-entry with the split functions and stick the EBP retrieval between them. Fixes: 27d6b4d14f5c ("x86/entry: Use generic syscall entry function") Reported-by: Andy Lutomirski <luto@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/87k0xdjbtt.fsf@nanos.tec.linutronix.de
2020-07-26Merge branch 'locking/nmi' into x86/entryIngo Molnar1-0/+34
Resolve conflicts with ongoing lockdep work that fixed the NMI entry code. Conflicts: arch/x86/entry/common.c arch/x86/include/asm/idtentry.h Signed-off-by: Ingo Molnar <mingo@kernel.org>
2020-07-24x86/entry: Cleanup idtentry_enter/exitThomas Gleixner1-3/+3
Remove the temporary defines and fixup all references. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Kees Cook <keescook@chromium.org> Link: https://lkml.kernel.org/r/20200722220520.855839271@linutronix.de
2020-07-24x86/entry: Use generic interrupt entry/exit codeThomas Gleixner1-166/+1
Replace the x86 code with the generic variant. Use temporary defines for idtentry_* which will be cleaned up in the next step. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/20200722220520.711492752@linutronix.de
2020-07-24x86/entry: Use generic syscall exit functionalityThomas Gleixner1-216/+5
Replace the x86 variant with the generic version. Provide the relevant architecture specific helper functions and defines. Use a temporary define for idtentry_exit_user which will be cleaned up seperately. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Kees Cook <keescook@chromium.org> Link: https://lkml.kernel.org/r/20200722220520.494648601@linutronix.de
2020-07-24x86/entry: Use generic syscall entry functionThomas Gleixner1-173/+8
Replace the syscall entry work handling with the generic version. Provide the necessary helper inlines to handle the real architecture specific parts, e.g. ptrace. Use a temporary define for idtentry_enter_user which will be cleaned up seperately. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Kees Cook <keescook@chromium.org> Link: https://lkml.kernel.org/r/20200722220520.376213694@linutronix.de
2020-07-24x86/entry: Move user return notifier out of loopThomas Gleixner1-4/+4
Guests and user space share certain MSRs. KVM sets these MSRs to guest values once and does not set them back to user space values on every VM exit to spare the costly MSR operations. User return notifiers ensure that these MSRs are set back to the correct values before returning to user space in exit_to_usermode_loop(). There is no reason to evaluate the TIF flag indicating that user return notifiers need to be invoked in the loop. The important point is that they are invoked before returning to user space. Move the invocation out of the loop into the section which does the last preperatory steps before returning to user space. That section is not preemptible and runs with interrupts disabled until the actual return. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/20200722220520.159112003@linutronix.de
2020-07-24x86/entry: Consolidate 32/64 bit syscall entryThomas Gleixner1-52/+41
64bit and 32bit entry code have the same open coded syscall entry handling after the bitwidth specific bits. Move it to a helper function and share the code. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/20200722220520.051234096@linutronix.de
2020-07-24x86/entry: Consolidate check_user_regs()Thomas Gleixner1-15/+9
The user register sanity check is sprinkled all over the place. Move it into enter_from_user_mode(). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Kees Cook <keescook@chromium.org> Link: https://lkml.kernel.org/r/20200722220519.943016204@linutronix.de
2020-07-10x86/entry: Fix NMI vs IRQ state trackingPeter Zijlstra1-4/+38
While the nmi_enter() users did trace_hardirqs_{off_prepare,on_finish}() there was no matching lockdep_hardirqs_*() calls to complete the picture. Introduce idtentry_{enter,exit}_nmi() to enable proper IRQ state tracking across the NMIs. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Ingo Molnar <mingo@kernel.org> Link: https://lkml.kernel.org/r/20200623083721.216740948@infradead.org
2020-07-10Merge branch 'x86/urgent' into x86/entry to pick up upstream fixes.Thomas Gleixner1-2/+2
2020-07-09x86/entry/common: Make prepare_exit_to_usermode() staticThomas Gleixner1-1/+1
No users outside this file anymore. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Andy Lutomirski <luto@kernel.org> Link: https://lkml.kernel.org/r/20200708192934.301116609@linutronix.de
2020-07-09x86/entry: Mark check_user_regs() noinstrThomas Gleixner1-1/+1
It's called from the non-instrumentable section. Fixes: c9c26150e61d ("x86/entry: Assert that syscalls are on the right stack") Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Andy Lutomirski <luto@kernel.org> Link: https://lkml.kernel.org/r/20200708192934.191497962@linutronix.de
2020-07-06x86/entry: Rename idtentry_enter/exit_cond_rcu() to idtentry_enter/exit()Andy Lutomirski1-22/+28
They were originally called _cond_rcu because they were special versions with conditional RCU handling. Now they're the standard entry and exit path, so the _cond_rcu part is just confusing. Drop it. Also change the signature to make them more extensible and more foolproof. No functional change -- it's pure refactoring. Signed-off-by: Andy Lutomirski <luto@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/247fc67685263e0b673e1d7f808182d28ff80359.1593795633.git.luto@kernel.org
2020-07-04x86/entry, selftests: Further improve user entry sanity checksAndy Lutomirski1-0/+19
Chasing down a Xen bug caused me to realize that the new entry sanity checks are still fairly weak. Add some more checks. Signed-off-by: Andy Lutomirski <luto@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/881de09e786ab93ce56ee4a2437ba2c308afe7a9.1593795633.git.luto@kernel.org
2020-07-01x86/entry: Move SYSENTER's regs->sp and regs->flags fixups into CAndy Lutomirski1-0/+12
The SYSENTER asm (32-bit and compat) contains fixups for regs->sp and regs->flags. Move the fixups into C and fix some comments while at it. This is a valid cleanup all by itself, and it also simplifies the subsequent patch that will fix Xen PV SYSENTER. Signed-off-by: Andy Lutomirski <luto@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/fe62bef67eda7fac75b8f3dbafccf571dc4ece6b.1593191971.git.luto@kernel.org
2020-07-01x86/entry: Assert that syscalls are on the right stackAndy Lutomirski1-3/+15
Now that the entry stack is a full page, it's too easy to regress the system call entry code and end up on the wrong stack without noticing. Assert that all system calls (SYSCALL64, SYSCALL32, SYSENTER, and INT80) are on the right stack and have pt_regs in the right place. Signed-off-by: Andy Lutomirski <luto@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/52059e42bb0ab8551153d012d68f7be18d72ff8e.1593191971.git.luto@kernel.org
2020-06-12x86/entry: Force rcu_irq_enter() when in idle taskThomas Gleixner1-7/+28
The idea of conditionally calling into rcu_irq_enter() only when RCU is not watching turned out to be not completely thought through. Paul noticed occasional premature end of grace periods in RCU torture testing. Bisection led to the commit which made the invocation of rcu_irq_enter() conditional on !rcu_is_watching(). It turned out that this conditional breaks RCU assumptions about the idle task when the scheduler tick happens to be a nested interrupt. Nested interrupts can happen when the first interrupt invokes softirq processing on return which enables interrupts. If that nested tick interrupt does not invoke rcu_irq_enter() then the RCU's irq-nesting checks will believe that this interrupt came directly from idle, which will cause RCU to report a quiescent state. Because this interrupt instead came from a softirq handler which might have been executing an RCU read-side critical section, this can cause the grace period to end prematurely. Change the condition from !rcu_is_watching() to is_idle_task(current) which enforces that interrupts in the idle task unconditionally invoke rcu_irq_enter() independent of the RCU state. This is also correct vs. user mode entries in NOHZ full scenarios because user mode entries bring RCU out of EQS and force the RCU irq nesting state accounting to nested. As only the first interrupt can enter from user mode a nested tick interrupt will enter from kernel mode and as the nesting state accounting is forced to nesting it will not do anything stupid even if rcu_irq_enter() has not been invoked. Fixes: 3eeec3858488 ("x86/entry: Provide idtentry_entry/exit_cond_rcu()") Reported-by: "Paul E. McKenney" <paulmck@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: "Paul E. McKenney" <paulmck@kernel.org> Reviewed-by: "Paul E. McKenney" <paulmck@kernel.org> Acked-by: Andy Lutomirski <luto@kernel.org> Acked-by: Frederic Weisbecker <frederic@kernel.org> Link: https://lkml.kernel.org/r/87wo4cxubv.fsf@nanos.tec.linutronix.de
2020-06-11x86/entry: Rename trace_hardirqs_off_prepare()Peter Zijlstra1-3/+3
The typical pattern for trace_hardirqs_off_prepare() is: ENTRY lockdep_hardirqs_off(); // because hardware ... do entry magic instrumentation_begin(); trace_hardirqs_off_prepare(); ... do actual work trace_hardirqs_on_prepare(); lockdep_hardirqs_on_prepare(); instrumentation_end(); ... do exit magic lockdep_hardirqs_on(); which shows that it's named wrong, rename it to trace_hardirqs_off_finish(), as it concludes the hardirq_off transition. Also, given that the above is the only correct order, make the traditional all-in-one trace_hardirqs_off() follow suit. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/20200529213321.415774872@infradead.org
2020-06-11x86/entry: Make enter_from_user_mode() staticThomas Gleixner1-1/+1
The ASM users are gone. All callers are local. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@kernel.org> Acked-by: Andy Lutomirski <luto@kernel.org> Link: https://lore.kernel.org/r/20200521202120.129232680@linutronix.de
2020-06-11x86/entry: Switch XEN/PV hypercall entry to IDTENTRYThomas Gleixner1-0/+78
Convert the XEN/PV hypercall to IDTENTRY: - Emit the ASM stub with DECLARE_IDTENTRY - Remove the ASM idtentry in 64-bit - Remove the open coded ASM entry code in 32-bit - Remove the old prototypes The handler stubs need to stay in ASM code as they need corner case handling and adjustment of the stack pointer. Provide a new C function which invokes the entry/exit handling and calls into the XEN handler on the interrupt stack if required. The exit code is slightly different from the regular idtentry_exit() on non-preemptible kernels. If the hypercall is preemptible and need_resched() is set then XEN provides a preempt hypercall scheduling function. Move this functionality into the entry code so it can use the existing idtentry functionality. [ mingo: Build fixes. ] Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@kernel.org> Acked-by: Andy Lutomirski <luto@kernel.org> Acked-by: Juergen Gross <jgross@suse.com> Tested-by: Juergen Gross <jgross@suse.com> Link: https://lore.kernel.org/r/20200521202118.055270078@linutronix.de
2020-06-11x86/entry: Split out idtentry_exit_cond_resched()Thomas Gleixner1-15/+15
The XEN PV hypercall requires the ability of conditional rescheduling when preemption is disabled because some hypercalls take ages. Split out the rescheduling code from idtentry_exit_cond_rcu() so it can be reused for that. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@kernel.org> Acked-by: Andy Lutomirski <luto@kernel.org> Link: https://lore.kernel.org/r/20200521202117.962199649@linutronix.de
2020-06-11x86/entry: Clean up idtentry_enter/exit() leftoversThomas Gleixner1-38/+29
Now that everything is converted to conditional RCU handling remove idtentry_enter/exit() and tidy up the conditional functions. This does not remove rcu_irq_exit_preempt(), to avoid conflicts with the RCU tree. Will be removed once all of this hits Linus's tree. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@kernel.org> Acked-by: Andy Lutomirski <luto@kernel.org> Link: https://lore.kernel.org/r/20200521202117.473597954@linutronix.de
2020-06-11x86/entry: Provide idtentry_enter/exit_user()Thomas Gleixner1-0/+31
As there are exceptions which already handle entry from user mode and from kernel mode separately, providing explicit user entry/exit handling callbacks makes sense and makes the code easier to understand. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@kernel.org> Acked-by: Andy Lutomirski <luto@kernel.org> Link: https://lore.kernel.org/r/20200521202117.289548561@linutronix.de
2020-06-11x86/entry: Provide idtentry_entry/exit_cond_rcu()Thomas Gleixner1-15/+64
After a lengthy discussion [1] it turned out that RCU does not need a full rcu_irq_enter/exit() when RCU is already watching. All it needs if NOHZ_FULL is active is to check whether the tick needs to be restarted. This allows to avoid a separate variant for the pagefault handler which cannot invoke rcu_irq_enter() on a kernel pagefault which might sleep. The cond_rcu argument is only temporary and will be removed once the existing users of idtentry_enter/exit() have been cleaned up. After that the code can be significantly simplified. [ mingo: Simplified the control flow ] Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@kernel.org> Acked-by: "Paul E. McKenney" <paulmck@kernel.org> Acked-by: Andy Lutomirski <luto@kernel.org> Link: [1] https://lkml.kernel.org/r/20200515235125.628629605@linutronix.de Link: https://lore.kernel.org/r/20200521202117.181397835@linutronix.de
2020-06-11x86/entry/common: Provide idtentry_enter/exit()Thomas Gleixner1-0/+99
Provide functions which handle the low level entry and exit similar to enter/exit from user mode. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com> Acked-by: Peter Zijlstra <peterz@infradead.org> Acked-by: Andy Lutomirski <luto@kernel.org> Link: https://lkml.kernel.org/r/20200505134904.457578656@linutronix.de
2020-06-11x86/entry: Move irq flags tracing to prepare_exit_to_usermode()Thomas Gleixner1-1/+18
This is another step towards more C-code and less convoluted ASM. Similar to the entry path, invoke the tracer before context tracking which might turn off RCU and invoke lockdep as the last step before going back to user space. Annotate the code sections in exit_to_user_mode() accordingly so objtool won't complain about the tracer invocation. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com> Acked-by: Peter Zijlstra <peterz@infradead.org> Acked-by: Andy Lutomirski <luto@kernel.org> Link: https://lkml.kernel.org/r/20200505134340.703783926@linutronix.de
2020-06-11x86/entry: Move irq tracing on syscall entry to C-codeThomas Gleixner1-2/+19
Now that the C entry points are safe, move the irq flags tracing code into the entry helper: - Invoke lockdep before calling into context tracking - Use the safe trace_hardirqs_on_prepare() trace function after context tracking established state and RCU is watching. enter_from_user_mode() is also still invoked from the exception/interrupt entry code which still contains the ASM irq flags tracing. So this is just a redundant and harmless invocation of tracing / lockdep until these are removed as well. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com> Acked-by: Peter Zijlstra <peterz@infradead.org> Link: https://lkml.kernel.org/r/20200505134340.611961721@linutronix.de
2020-06-11x86/entry/common: Protect against instrumentationThomas Gleixner1-44/+89
Mark the various syscall entries with noinstr to protect them against instrumentation and add the noinstrumentation_begin()/end() annotations to mark the parts of the functions which are safe to call out into instrumentable code. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com> Acked-by: Peter Zijlstra <peterz@infradead.org> Link: https://lkml.kernel.org/r/20200505134340.520277507@linutronix.de
2020-06-11x86/entry: Mark enter_from_user_mode() noinstrThomas Gleixner1-1/+1
Both the callers in the low level ASM code and __context_tracking_exit() which is invoked from enter_from_user_mode() via user_exit_irqoff() are marked NOKPROBE. Allowing enter_from_user_mode() to be probed is inconsistent at best. Aside of that while function tracing per se is safe the function trace entry/exit points can be used via BPF as well which is not safe to use before context tracking has reached CONTEXT_KERNEL and adjusted RCU. Mark it noinstr which moves it into the instrumentation protected text section and includes notrace. Note, this needs further fixups in context tracking to ensure that the full call chain is protected. Will be addressed in follow up changes. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org> Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com> Acked-by: Peter Zijlstra <peterz@infradead.org> Link: https://lkml.kernel.org/r/20200505134340.429059405@linutronix.de
2020-03-31Merge branch 'x86-cleanups-for-linus' of ↵Linus Torvalds1-0/+1
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 cleanups from Ingo Molnar: "This topic tree contains more commits than usual: - most of it are uaccess cleanups/reorganization by Al - there's a bunch of prototype declaration (--Wmissing-prototypes) cleanups - misc other cleanups all around the map" * 'x86-cleanups-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (36 commits) x86/mm/set_memory: Fix -Wmissing-prototypes warnings x86/efi: Add a prototype for efi_arch_mem_reserve() x86/mm: Mark setup_emu2phys_nid() static x86/jump_label: Move 'inline' keyword placement x86/platform/uv: Add a missing prototype for uv_bau_message_interrupt() kill uaccess_try() x86: unsafe_put-style macro for sigmask x86: x32_setup_rt_frame(): consolidate uaccess areas x86: __setup_rt_frame(): consolidate uaccess areas x86: __setup_frame(): consolidate uaccess areas x86: setup_sigcontext(): list user_access_{begin,end}() into callers x86: get rid of put_user_try in __setup_rt_frame() (both 32bit and 64bit) x86: ia32_setup_rt_frame(): consolidate uaccess areas x86: ia32_setup_frame(): consolidate uaccess areas x86: ia32_setup_sigcontext(): lift user_access_{begin,end}() into the callers x86/alternatives: Mark text_poke_loc_init() static x86/cpu: Fix a -Wmissing-prototypes warning for init_ia32_feat_ctl() x86/mm: Drop pud_mknotpresent() x86: Replace setup_irq() by request_irq() x86/configs: Slightly reduce defconfigs ...
2020-03-21x86/entry/32: Enable pt_regs based syscallsBrian Gerst1-15/+0
Enable pt_regs based syscalls for 32-bit. This makes the 32-bit native kernel consistent with the 64-bit kernel, and improves the syscall interface by not needing to push all 6 potential arguments onto the stack. Signed-off-by: Brian Gerst <brgerst@gmail.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net> Link: https://lkml.kernel.org/r/20200313195144.164260-17-brgerst@gmail.com
2020-03-21x86/entry/64: Move sys_ni_syscall stub to common.cBrian Gerst1-0/+7
so it can be available to multiple syscall tables. Also directly return -ENOSYS instead of bouncing to the generic sys_ni_syscall(). Signed-off-by: Brian Gerst <brgerst@gmail.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/20200313195144.164260-7-brgerst@gmail.com
2020-02-17x86/syscalls: Add prototypes for C syscall callbacksBenjamin Thiel1-0/+1
.. in order to fix a couple of -Wmissing-prototypes warnings. No functional change. [ bp: Massage commit message and drop newlines. ] Signed-off-by: Benjamin Thiel <b.thiel@posteo.de> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/20200123152754.20149-1-b.thiel@posteo.de
2019-11-16x86/ioperm: Move TSS bitmap update to exit to user workThomas Gleixner1-0/+4
There is no point to update the TSS bitmap for tasks which use I/O bitmaps on every context switch. It's enough to update it right before exiting to user space. That reduces the context switch bitmap handling to invalidating the io bitmap base offset in the TSS when the outgoing task has TIF_IO_BITMAP set. The invaldiation is done on purpose when a task with an IO bitmap switches out to prevent any possible leakage of an activated IO bitmap. It also removes the requirement to update the tasks bitmap atomically in ioperm(). Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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