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2024-04-10riscv: Fix spurious errors from __get/put_kernel_nofaultSamuel Holland1-2/+2
commit d080a08b06b6266cc3e0e86c5acfd80db937cb6b upstream. These macros did not initialize __kr_err, so they could fail even if the access did not fault. Cc: stable@vger.kernel.org Fixes: d464118cdc41 ("riscv: implement __get_kernel_nofault and __put_user_nofault") Signed-off-by: Samuel Holland <samuel.holland@sifive.com> Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com> Reviewed-by: Charlie Jenkins <charlie@rivosinc.com> Link: https://lore.kernel.org/r/20240312022030.320789-1-samuel.holland@sifive.com Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-01-05riscv: uaccess: fix type of 0 variable on error in get_user()Ben Dooks1-1/+1
If the get_user(x, ptr) has x as a pointer, then the setting of (x) = 0 is going to produce the following sparse warning, so fix this by forcing the type of 'x' when access_ok() fails. fs/aio.c:2073:21: warning: Using plain integer as NULL pointer Signed-off-by: Ben Dooks <ben-linux@fluff.org> Reviewed-by: Palmer Dabbelt <palmer@rivosinc.com> Link: https://lore.kernel.org/r/20221229170545.718264-1-ben-linux@fluff.org Cc: stable@vger.kernel.org Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2022-02-25uaccess: generalize access_ok()Arnd Bergmann1-30/+1
There are many different ways that access_ok() is defined across architectures, but in the end, they all just compare against the user_addr_max() value or they accept anything. Provide one definition that works for most architectures, checking against TASK_SIZE_MAX for user processes or skipping the check inside of uaccess_kernel() sections. For architectures without CONFIG_SET_FS(), this should be the fastest check, as it comes down to a single comparison of a pointer against a compile-time constant, while the architecture specific versions tend to do something more complex for historic reasons or get something wrong. Type checking for __user annotations is handled inconsistently across architectures, but this is easily simplified as well by using an inline function that takes a 'const void __user *' argument. A handful of callers need an extra __user annotation for this. Some architectures had trick to use 33-bit or 65-bit arithmetic on the addresses to calculate the overflow, however this simpler version uses fewer registers, which means it can produce better object code in the end despite needing a second (statically predicted) branch. Reviewed-by: Christoph Hellwig <hch@lst.de> Acked-by: Mark Rutland <mark.rutland@arm.com> [arm64, asm-generic] Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> Acked-by: Stafford Horne <shorne@gmail.com> Acked-by: Dinh Nguyen <dinguyen@kernel.org> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2022-02-25uaccess: add generic __{get,put}_kernel_nofaultArnd Bergmann1-2/+0
Nine architectures are still missing __{get,put}_kernel_nofault: alpha, ia64, microblaze, nds32, nios2, openrisc, sh, sparc32, xtensa. Add a generic version that lets everything use the normal copy_{from,to}_kernel_nofault() code based on these, removing the last use of get_fs()/set_fs() from architecture-independent code. Reviewed-by: Christoph Hellwig <hch@lst.de> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2022-01-06riscv: extable: add a dedicated uaccess handlerJisheng Zhang1-53/+22
Inspired by commit 2e77a62cb3a6 ("arm64: extable: add a dedicated uaccess handler"), do similar to riscv to add a dedicated uaccess exception handler to update registers in exception context and subsequently return back into the function which faulted, so we remove the need for fixups specialized to each faulting instruction. Signed-off-by: Jisheng Zhang <jszhang@kernel.org> Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2022-01-06riscv: extable: consolidate definitionsJisheng Zhang1-6/+1
This is a riscv port of commit 819771cc2892 ("arm64: extable: consolidate definitions"). Signed-off-by: Jisheng Zhang <jszhang@kernel.org> Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2022-01-06riscv: switch to relative exception tablesJisheng Zhang1-2/+2
Similar as other architectures such as arm64, x86 and so on, use offsets relative to the exception table entry values rather than absolute addresses for both the exception locationand the fixup. However, RISCV label difference will actually produce two relocations, a pair of R_RISCV_ADD32 and R_RISCV_SUB32. Take below simple code for example: $ cat test.S .section .text 1: nop .section __ex_table,"a" .balign 4 .long (1b - .) .previous $ riscv64-linux-gnu-gcc -c test.S $ riscv64-linux-gnu-readelf -r test.o Relocation section '.rela__ex_table' at offset 0x100 contains 2 entries: Offset Info Type Sym. Value Sym. Name + Addend 000000000000 000600000023 R_RISCV_ADD32 0000000000000000 .L1^B1 + 0 000000000000 000500000027 R_RISCV_SUB32 0000000000000000 .L0 + 0 The modpost will complain the R_RISCV_SUB32 relocation, so we need to patch modpost.c to skip this relocation for .rela__ex_table section. After this patch, the __ex_table section size of defconfig vmlinux is reduced from 7072 Bytes to 3536 Bytes. Signed-off-by: Jisheng Zhang <jszhang@kernel.org> Reviewed-by: Kefeng Wang <wangkefeng.wang@huawei.com> Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2022-01-06riscv: consolidate __ex_table constructionJisheng Zhang1-18/+12
Consolidate all the __ex_table constuction code with a _ASM_EXTABLE helper. There should be no functional change as a result of this patch. Signed-off-by: Jisheng Zhang <jszhang@kernel.org> Reviewed-by: Kefeng Wang <wangkefeng.wang@huawei.com> Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2022-01-06riscv: remove unused __cmpxchg_user() macroJisheng Zhang1-75/+0
This macro is defined but not used, remove it. Signed-off-by: Jisheng Zhang <jszhang@kernel.org> Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2021-05-02Merge branch 'work.misc' of ↵Linus Torvalds1-1/+0
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull misc vfs updates from Al Viro: "Assorted stuff all over the place" * 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: useful constants: struct qstr for ".." hostfs_open(): don't open-code file_dentry() whack-a-mole: kill strlen_user() (again) autofs: should_expire() argument is guaranteed to be positive apparmor:match_mn() - constify devpath argument buffer: a small optimization in grow_buffers get rid of autofs_getpath() constify dentry argument of dentry_path()/dentry_path_raw()
2021-04-02riscv: evaluate put_user() arg before enabling user accessBen Dooks1-2/+5
The <asm/uaccess.h> header has a problem with put_user(a, ptr) if the 'a' is not a simple variable, such as a function. This can lead to the compiler producing code as so: 1: enable_user_access() 2: evaluate 'a' into register 'r' 3: put 'r' to 'ptr' 4: disable_user_acess() The issue is that 'a' is now being evaluated with the user memory protections disabled. So we try and force the evaulation by assigning 'x' to __val at the start, and hoping the compiler barriers in enable_user_access() do the job of ordering step 2 before step 1. This has shown up in a bug where 'a' sleeps and thus schedules out and loses the SR_SUM flag. This isn't sufficient to fully fix, but should reduce the window of opportunity. The first instance of this we found is in scheudle_tail() where the code does: $ less -N kernel/sched/core.c 4263 if (current->set_child_tid) 4264 put_user(task_pid_vnr(current), current->set_child_tid); Here, the task_pid_vnr(current) is called within the block that has enabled the user memory access. This can be made worse with KASAN which makes task_pid_vnr() a rather large call with plenty of opportunity to sleep. Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk> Reported-by: syzbot+e74b94fe601ab9552d69@syzkaller.appspotmail.com Suggested-by: Arnd Bergman <arnd@arndb.de> -- Changes since v1: - fixed formatting and updated the patch description with more info Changes since v2: - fixed commenting on __put_user() (schwab@linux-m68k.org) Change since v3: - fixed RFC in patch title. Should be ready to merge. Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2021-03-28whack-a-mole: kill strlen_user() (again)Al Viro1-1/+0
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-11-06riscv: uaccess: fix __put_kernel_nofault()Changbin Du1-1/+1
The copy_from_kernel_nofault() is broken on riscv because the 'dst' and 'src' are mistakenly reversed in __put_kernel_nofault() macro. copy_to_kernel_nofault: ... 0xffffffe0003159b8 <+30>: sd a4,0(a1) # a1 aka 'src' Fixes: d464118cdc ("riscv: implement __get_kernel_nofault and __put_user_nofault") Signed-off-by: Changbin Du <changbin.du@gmail.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Anup Patel <anup@brainfault.org> Tested-by: Anup Patel <anup@brainfault.org> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2020-10-04riscv: remove address space overrides using set_fs()Christoph Hellwig1-26/+1
Stop providing the possibility to override the address space using set_fs() now that there is no need for that any more. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2020-10-04riscv: implement __get_kernel_nofault and __put_user_nofaultChristoph Hellwig1-0/+20
Implement the non-faulting kernel access helpers directly instead of abusing the uaccess routines under set_fs(KERNEL_DS). Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2020-10-04riscv: refactor __get_user and __put_userChristoph Hellwig1-42/+52
Add new __get_user_nocheck and __put_user_nocheck that switch on the size and call the actual inline assembly helpers, and move the uaccess enable / disable into the actual __get_user and __put_user. This prepares for natively implementing __get_kernel_nofault and __put_kernel_nofault. Also don't bother with the deprecated register keyword for the error return. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2020-10-04riscv: use memcpy based uaccess for nommu againChristoph Hellwig1-18/+18
This reverts commit adccfb1a805ea84d2db38eb53032533279bdaa97. Now that the generic uaccess by mempcy code handles unaligned addresses the generic code can be used for all RISC-V CPUs. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2020-08-12uaccess: remove segment_eqChristoph Hellwig1-3/+1
segment_eq is only used to implement uaccess_kernel. Just open code uaccess_kernel in the arch uaccess headers and remove one layer of indirection. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Greentime Hu <green.hu@gmail.com> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Nick Hu <nickhu@andestech.com> Cc: Vincent Chen <deanbo422@gmail.com> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: Palmer Dabbelt <palmer@dabbelt.com> Link: http://lkml.kernel.org/r/20200710135706.537715-5-hch@lst.de Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-12riscv: include <asm/pgtable.h> in <asm/uaccess.h>Christoph Hellwig1-0/+2
To ensure TASK_SIZE is defined for USER_DS. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Palmer Dabbelt <palmerdabbelt@google.com> Cc: Nick Hu <nickhu@andestech.com> Cc: Greentime Hu <green.hu@gmail.com> Cc: Vincent Chen <deanbo422@gmail.com> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Link: http://lkml.kernel.org/r/20200710135706.537715-4-hch@lst.de Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-03-19riscv: uaccess should be used in nommu modeGreentime Hu1-18/+18
It might have the unaligned access exception when trying to exchange data with user space program. In this case, it failed in tty_ioctl(). Therefore we should enable uaccess.S for NOMMU mode since the generic code doesn't handle the unaligned access cases. 0x8013a212 <tty_ioctl+462>: ld a5,460(s1) [ 0.115279] Oops - load address misaligned [#1] [ 0.115284] CPU: 0 PID: 29 Comm: sh Not tainted 5.4.0-rc5-00020-gb4c27160d562-dirty #36 [ 0.115294] epc: 000000008013a212 ra : 000000008013a212 sp : 000000008f48dd50 [ 0.115303] gp : 00000000801cac28 tp : 000000008fb80000 t0 : 00000000000000e8 [ 0.115312] t1 : 000000008f58f108 t2 : 0000000000000009 s0 : 000000008f48ddf0 [ 0.115321] s1 : 000000008f8c6220 a0 : 0000000000000001 a1 : 000000008f48dd28 [ 0.115330] a2 : 000000008fb80000 a3 : 00000000801a7398 a4 : 0000000000000000 [ 0.115339] a5 : 0000000000000000 a6 : 000000008f58f0c6 a7 : 000000000000001d [ 0.115348] s2 : 000000008f8c6308 s3 : 000000008f78b7c8 s4 : 000000008fb834c0 [ 0.115357] s5 : 0000000000005413 s6 : 0000000000000000 s7 : 000000008f58f2b0 [ 0.115366] s8 : 000000008f858008 s9 : 000000008f776818 s10: 000000008f776830 [ 0.115375] s11: 000000008fb840a8 t3 : 1999999999999999 t4 : 000000008f78704c [ 0.115384] t5 : 0000000000000005 t6 : 0000000000000002 [ 0.115391] status: 0000000200001880 badaddr: 000000008f8c63ec cause: 0000000000000004 [ 0.115401] ---[ end trace 00d490c6a8b6c9ac ]--- This failure could be fixed after this patch applied. [ 0.002282] Run /init as init process Initializing random number generator... [ 0.005573] random: dd: uninitialized urandom read (512 bytes read) done. Welcome to Buildroot buildroot login: root Password: Jan 1 00:00:00 login[62]: root login on 'ttySIF0' ~ # Signed-off-by: Greentime Hu <greentime.hu@sifive.com> Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2019-11-18riscv: add nommu supportChristoph Hellwig1-0/+4
The kernel runs in M-mode without using page tables, and thus can't run bare metal without help from additional firmware. Most of the patch is just stubbing out code not needed without page tables, but there is an interesting detail in the signals implementation: - The normal RISC-V syscall ABI only implements rt_sigreturn as VDSO entry point, but the ELF VDSO is not supported for nommu Linux. We instead copy the code to call the syscall onto the stack. In addition to enabling the nommu code a new defconfig for a small kernel image that can run in nommu mode on qemu is also provided, to run a kernel in qemu you can use the following command line: qemu-system-riscv64 -smp 2 -m 64 -machine virt -nographic \ -kernel arch/riscv/boot/loader \ -drive file=rootfs.ext2,format=raw,id=hd0 \ -device virtio-blk-device,drive=hd0 Contains contributions from Damien Le Moal <Damien.LeMoal@wdc.com>. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Anup Patel <anup@brainfault.org> [paul.walmsley@sifive.com: updated to apply; add CONFIG_MMU guards around PCI_IOBASE definition to fix build issues; fixed checkpatch issues; move the PCI_IO_* and VMEMMAP address space macros along with the others; resolve sparse warning] Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>
2019-06-05treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 286Thomas Gleixner1-9/+1
Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation version 2 this program is distributed in the hope that it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 97 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Reviewed-by: Alexios Zavras <alexios.zavras@intel.com> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190529141901.025053186@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-04-26riscv: remove unreachable big endian codeChristoph Hellwig1-8/+1
RISC-V is always little endian. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
2019-04-26riscv: turn mm_segment_t into a structChristoph Hellwig1-5/+7
This matches what other heavily used architectures do, and will allow us to easily use <asm-generic/uaccess.h> for the nommu case. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
2019-04-26riscv: use asm-generic/extable.hChristoph Hellwig1-6/+1
Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
2019-03-27riscv: fix accessing 8-byte variable from RV32Alan Kao1-1/+1
A memory save operation to 8-byte variable in RV32 is divided into two sw instructions in the put_user macro. The current fixup returns execution flow to the second sw instead of the one after it. This patch fixes this fixup code according to the load access part. Signed-off-by: Alan Kao<alankao@andestech.com> Cc: Greentime Hu <greentime@andestech.com> Cc: Vincent Chen <deanbo422@gmail.com> Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
2019-03-04get rid of legacy 'get_ds()' functionLinus Torvalds1-1/+0
Every in-kernel use of this function defined it to KERNEL_DS (either as an actual define, or as an inline function). It's an entirely historical artifact, and long long long ago used to actually read the segment selector valueof '%ds' on x86. Which in the kernel is always KERNEL_DS. Inspired by a patch from Jann Horn that just did this for a very small subset of users (the ones in fs/), along with Al who suggested a script. I then just took it to the logical extreme and removed all the remaining gunk. Roughly scripted with git grep -l '(get_ds())' -- :^tools/ | xargs sed -i 's/(get_ds())/(KERNEL_DS)/' git grep -lw 'get_ds' -- :^tools/ | xargs sed -i '/^#define get_ds()/d' plus manual fixups to remove a few unusual usage patterns, the couple of inline function cases and to fix up a comment that had become stale. The 'get_ds()' function remains in an x86 kvm selftest, since in user space it actually does something relevant. Inspired-by: Jann Horn <jannh@google.com> Inspired-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-01-04Remove 'type' argument from access_ok() functionLinus Torvalds1-10/+4
Nobody has actually used the type (VERIFY_READ vs VERIFY_WRITE) argument of the user address range verification function since we got rid of the old racy i386-only code to walk page tables by hand. It existed because the original 80386 would not honor the write protect bit when in kernel mode, so you had to do COW by hand before doing any user access. But we haven't supported that in a long time, and these days the 'type' argument is a purely historical artifact. A discussion about extending 'user_access_begin()' to do the range checking resulted this patch, because there is no way we're going to move the old VERIFY_xyz interface to that model. And it's best done at the end of the merge window when I've done most of my merges, so let's just get this done once and for all. This patch was mostly done with a sed-script, with manual fix-ups for the cases that weren't of the trivial 'access_ok(VERIFY_xyz' form. There were a couple of notable cases: - csky still had the old "verify_area()" name as an alias. - the iter_iov code had magical hardcoded knowledge of the actual values of VERIFY_{READ,WRITE} (not that they mattered, since nothing really used it) - microblaze used the type argument for a debug printout but other than those oddities this should be a total no-op patch. I tried to fix up all architectures, did fairly extensive grepping for access_ok() uses, and the changes are trivial, but I may have missed something. Any missed conversion should be trivially fixable, though. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-11-20RISC-V: Fix raw_copy_{to,from}_user()Olof Johansson1-2/+2
Sparse highlighted it, and appears to be a pure bug (from vs to). ./arch/riscv/include/asm/uaccess.h:403:35: warning: incorrect type in argument 1 (different address spaces) ./arch/riscv/include/asm/uaccess.h:403:39: warning: incorrect type in argument 2 (different address spaces) ./arch/riscv/include/asm/uaccess.h:409:37: warning: incorrect type in argument 1 (different address spaces) ./arch/riscv/include/asm/uaccess.h:409:41: warning: incorrect type in argument 2 (different address spaces) Signed-off-by: Olof Johansson <olof@lixom.net> Cc: stable@vger.kernel.org Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
2018-06-09riscv: split the declaration of __copy_userLuc Van Oostenryck1-3/+5
We use a single __copy_user assembly function to copy memory both from and to userspace. While this works, it triggers sparse errors because we're implicitly casting between the kernel and user address spaces by calling __copy_user. This patch splits the C declaration into a pair of functions, __asm_copy_{to,from}_user, that have sane semantics WRT __user. This split make things fine from sparse's point of view. The assembly implementation keeps a single definition but add a double ENTRY() for it, one for __asm_copy_to_user and another one for __asm_copy_from_user. The result is a spare-safe implementation that pays no performance or code size penalty. Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com> Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
2018-01-08riscv: remove CONFIG_MMU ifdefsChristoph Hellwig1-12/+0
The RISC-V port doesn't suport a nommu mode, so there is no reason to provide some code only under a CONFIG_MMU ifdef. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
2017-09-27RISC-V: Generic library routines and assemblyPalmer Dabbelt1-0/+513
This patch contains code that is more specific to the RISC-V ISA than it is to Linux. It contains string and math operations, C wrappers for various assembly instructions, stack walking code, and uaccess. Signed-off-by: Palmer Dabbelt <palmer@dabbelt.com>
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