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authorLinus Torvalds <torvalds@linux-foundation.org>2022-12-14 01:31:47 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2022-12-14 01:31:47 +0300
commitfc4c9f450493daef1c996c9d4b3c647ec3121509 (patch)
tree99078a5d34ba783b9b43092fe2c275784c7cab98 /arch/arm64
parent717e6eb49bdd98357d14c90d60a3409196b33cfc (diff)
parente8dfdf3162eb549d064b8c10b1564f7e8ee82591 (diff)
downloadlinux-fc4c9f450493daef1c996c9d4b3c647ec3121509.tar.xz
Merge tag 'efi-next-for-v6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi
Pull EFI updates from Ard Biesheuvel: "Another fairly sizable pull request, by EFI subsystem standards. Most of the work was done by me, some of it in collaboration with the distro and bootloader folks (GRUB, systemd-boot), where the main focus has been on removing pointless per-arch differences in the way EFI boots a Linux kernel. - Refactor the zboot code so that it incorporates all the EFI stub logic, rather than calling the decompressed kernel as a EFI app. - Add support for initrd= command line option to x86 mixed mode. - Allow initrd= to be used with arbitrary EFI accessible file systems instead of just the one the kernel itself was loaded from. - Move some x86-only handling and manipulation of the EFI memory map into arch/x86, as it is not used anywhere else. - More flexible handling of any random seeds provided by the boot environment (i.e., systemd-boot) so that it becomes available much earlier during the boot. - Allow improved arch-agnostic EFI support in loaders, by setting a uniform baseline of supported features, and adding a generic magic number to the DOS/PE header. This should allow loaders such as GRUB or systemd-boot to reduce the amount of arch-specific handling substantially. - (arm64) Run EFI runtime services from a dedicated stack, and use it to recover from synchronous exceptions that might occur in the firmware code. - (arm64) Ensure that we don't allocate memory outside of the 48-bit addressable physical range. - Make EFI pstore record size configurable - Add support for decoding CXL specific CPER records" * tag 'efi-next-for-v6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi: (43 commits) arm64: efi: Recover from synchronous exceptions occurring in firmware arm64: efi: Execute runtime services from a dedicated stack arm64: efi: Limit allocations to 48-bit addressable physical region efi: Put Linux specific magic number in the DOS header efi: libstub: Always enable initrd command line loader and bump version efi: stub: use random seed from EFI variable efi: vars: prohibit reading random seed variables efi: random: combine bootloader provided RNG seed with RNG protocol output efi/cper, cxl: Decode CXL Error Log efi/cper, cxl: Decode CXL Protocol Error Section efi: libstub: fix efi_load_initrd_dev_path() kernel-doc comment efi: x86: Move EFI runtime map sysfs code to arch/x86 efi: runtime-maps: Clarify purpose and enable by default for kexec efi: pstore: Add module parameter for setting the record size efi: xen: Set EFI_PARAVIRT for Xen dom0 boot on all architectures efi: memmap: Move manipulation routines into x86 arch tree efi: memmap: Move EFI fake memmap support into x86 arch tree efi: libstub: Undeprecate the command line initrd loader efi: libstub: Add mixed mode support to command line initrd loader efi: libstub: Permit mixed mode return types other than efi_status_t ...
Diffstat (limited to 'arch/arm64')
-rw-r--r--arch/arm64/include/asm/efi.h27
-rw-r--r--arch/arm64/kernel/Makefile9
-rw-r--r--arch/arm64/kernel/efi-entry.S69
-rw-r--r--arch/arm64/kernel/efi-rt-wrapper.S39
-rw-r--r--arch/arm64/kernel/efi.c49
-rw-r--r--arch/arm64/kernel/image-vars.h8
-rw-r--r--arch/arm64/mm/fault.c4
7 files changed, 114 insertions, 91 deletions
diff --git a/arch/arm64/include/asm/efi.h b/arch/arm64/include/asm/efi.h
index 439e2bc5d5d8..31d13a6001df 100644
--- a/arch/arm64/include/asm/efi.h
+++ b/arch/arm64/include/asm/efi.h
@@ -14,8 +14,16 @@
#ifdef CONFIG_EFI
extern void efi_init(void);
+
+bool efi_runtime_fixup_exception(struct pt_regs *regs, const char *msg);
#else
#define efi_init()
+
+static inline
+bool efi_runtime_fixup_exception(struct pt_regs *regs, const char *msg)
+{
+ return false;
+}
#endif
int efi_create_mapping(struct mm_struct *mm, efi_memory_desc_t *md);
@@ -25,6 +33,7 @@ int efi_set_mapping_permissions(struct mm_struct *mm, efi_memory_desc_t *md);
({ \
efi_virtmap_load(); \
__efi_fpsimd_begin(); \
+ spin_lock(&efi_rt_lock); \
})
#undef arch_efi_call_virt
@@ -33,10 +42,12 @@ int efi_set_mapping_permissions(struct mm_struct *mm, efi_memory_desc_t *md);
#define arch_efi_call_virt_teardown() \
({ \
+ spin_unlock(&efi_rt_lock); \
__efi_fpsimd_end(); \
efi_virtmap_unload(); \
})
+extern spinlock_t efi_rt_lock;
efi_status_t __efi_rt_asm_wrapper(void *, const char *, ...);
#define ARCH_EFI_IRQ_FLAGS_MASK (PSR_D_BIT | PSR_A_BIT | PSR_I_BIT | PSR_F_BIT)
@@ -76,13 +87,23 @@ static inline unsigned long efi_get_max_initrd_addr(unsigned long image_addr)
return (image_addr & ~(SZ_1G - 1UL)) + (1UL << (VA_BITS_MIN - 1));
}
-#define alloc_screen_info(x...) &screen_info
-
-static inline void free_screen_info(struct screen_info *si)
+static inline unsigned long efi_get_kimg_min_align(void)
{
+ extern bool efi_nokaslr;
+
+ /*
+ * Although relocatable kernels can fix up the misalignment with
+ * respect to MIN_KIMG_ALIGN, the resulting virtual text addresses are
+ * subtly out of sync with those recorded in the vmlinux when kaslr is
+ * disabled but the image required relocation anyway. Therefore retain
+ * 2M alignment if KASLR was explicitly disabled, even if it was not
+ * going to be activated to begin with.
+ */
+ return efi_nokaslr ? MIN_KIMG_ALIGN : EFI_KIMG_ALIGN;
}
#define EFI_ALLOC_ALIGN SZ_64K
+#define EFI_ALLOC_LIMIT ((1UL << 48) - 1)
/*
* On ARM systems, virtually remapped UEFI runtime services are set up in two
diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
index 8dd925f4a4c6..ceba6792f5b3 100644
--- a/arch/arm64/kernel/Makefile
+++ b/arch/arm64/kernel/Makefile
@@ -36,12 +36,6 @@ obj-y := debug-monitors.o entry.o irq.o fpsimd.o \
syscall.o proton-pack.o idreg-override.o idle.o \
patching.o
-targets += efi-entry.o
-
-OBJCOPYFLAGS := --prefix-symbols=__efistub_
-$(obj)/%.stub.o: $(obj)/%.o FORCE
- $(call if_changed,objcopy)
-
obj-$(CONFIG_COMPAT) += sys32.o signal32.o \
sys_compat.o
obj-$(CONFIG_COMPAT) += sigreturn32.o
@@ -57,8 +51,7 @@ obj-$(CONFIG_CPU_PM) += sleep.o suspend.o
obj-$(CONFIG_CPU_IDLE) += cpuidle.o
obj-$(CONFIG_JUMP_LABEL) += jump_label.o
obj-$(CONFIG_KGDB) += kgdb.o
-obj-$(CONFIG_EFI) += efi.o efi-entry.stub.o \
- efi-rt-wrapper.o
+obj-$(CONFIG_EFI) += efi.o efi-rt-wrapper.o
obj-$(CONFIG_PCI) += pci.o
obj-$(CONFIG_ARMV8_DEPRECATED) += armv8_deprecated.o
obj-$(CONFIG_ACPI) += acpi.o
diff --git a/arch/arm64/kernel/efi-entry.S b/arch/arm64/kernel/efi-entry.S
deleted file mode 100644
index 61a87fa1c305..000000000000
--- a/arch/arm64/kernel/efi-entry.S
+++ /dev/null
@@ -1,69 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0-only */
-/*
- * EFI entry point.
- *
- * Copyright (C) 2013, 2014 Red Hat, Inc.
- * Author: Mark Salter <msalter@redhat.com>
- */
-#include <linux/linkage.h>
-#include <linux/init.h>
-
-#include <asm/assembler.h>
-
- __INIT
-
-SYM_CODE_START(efi_enter_kernel)
- /*
- * efi_pe_entry() will have copied the kernel image if necessary and we
- * end up here with device tree address in x1 and the kernel entry
- * point stored in x0. Save those values in registers which are
- * callee preserved.
- */
- ldr w2, =primary_entry_offset
- add x19, x0, x2 // relocated Image entrypoint
- mov x20, x1 // DTB address
-
- /*
- * Clean the copied Image to the PoC, and ensure it is not shadowed by
- * stale icache entries from before relocation.
- */
- ldr w1, =kernel_size
- add x1, x0, x1
- bl dcache_clean_poc
- ic ialluis
-
- /*
- * Clean the remainder of this routine to the PoC
- * so that we can safely disable the MMU and caches.
- */
- adr x0, 0f
- adr x1, 3f
- bl dcache_clean_poc
-0:
- /* Turn off Dcache and MMU */
- mrs x0, CurrentEL
- cmp x0, #CurrentEL_EL2
- b.ne 1f
- mrs x0, sctlr_el2
- bic x0, x0, #1 << 0 // clear SCTLR.M
- bic x0, x0, #1 << 2 // clear SCTLR.C
- pre_disable_mmu_workaround
- msr sctlr_el2, x0
- isb
- b 2f
-1:
- mrs x0, sctlr_el1
- bic x0, x0, #1 << 0 // clear SCTLR.M
- bic x0, x0, #1 << 2 // clear SCTLR.C
- pre_disable_mmu_workaround
- msr sctlr_el1, x0
- isb
-2:
- /* Jump to kernel entry point */
- mov x0, x20
- mov x1, xzr
- mov x2, xzr
- mov x3, xzr
- br x19
-3:
-SYM_CODE_END(efi_enter_kernel)
diff --git a/arch/arm64/kernel/efi-rt-wrapper.S b/arch/arm64/kernel/efi-rt-wrapper.S
index 75691a2641c1..a00886410537 100644
--- a/arch/arm64/kernel/efi-rt-wrapper.S
+++ b/arch/arm64/kernel/efi-rt-wrapper.S
@@ -6,7 +6,7 @@
#include <linux/linkage.h>
SYM_FUNC_START(__efi_rt_asm_wrapper)
- stp x29, x30, [sp, #-32]!
+ stp x29, x30, [sp, #-112]!
mov x29, sp
/*
@@ -17,6 +17,22 @@ SYM_FUNC_START(__efi_rt_asm_wrapper)
stp x1, x18, [sp, #16]
/*
+ * Preserve all callee saved registers and preserve the stack pointer
+ * value at the base of the EFI runtime stack so we can recover from
+ * synchronous exceptions occurring while executing the firmware
+ * routines.
+ */
+ stp x19, x20, [sp, #32]
+ stp x21, x22, [sp, #48]
+ stp x23, x24, [sp, #64]
+ stp x25, x26, [sp, #80]
+ stp x27, x28, [sp, #96]
+
+ ldr_l x16, efi_rt_stack_top
+ mov sp, x16
+ stp x18, x29, [sp, #-16]!
+
+ /*
* We are lucky enough that no EFI runtime services take more than
* 5 arguments, so all are passed in registers rather than via the
* stack.
@@ -29,9 +45,10 @@ SYM_FUNC_START(__efi_rt_asm_wrapper)
mov x4, x6
blr x8
+ mov sp, x29
ldp x1, x2, [sp, #16]
cmp x2, x18
- ldp x29, x30, [sp], #32
+ ldp x29, x30, [sp], #112
b.ne 0f
ret
0:
@@ -42,6 +59,22 @@ SYM_FUNC_START(__efi_rt_asm_wrapper)
* called with preemption disabled and a separate shadow stack is used
* for interrupts.
*/
- mov x18, x2
+#ifdef CONFIG_SHADOW_CALL_STACK
+ ldr_l x18, efi_rt_stack_top
+ ldr x18, [x18, #-16]
+#endif
+
b efi_handle_corrupted_x18 // tail call
SYM_FUNC_END(__efi_rt_asm_wrapper)
+
+SYM_CODE_START(__efi_rt_asm_recover)
+ mov sp, x30
+
+ ldp x19, x20, [sp, #32]
+ ldp x21, x22, [sp, #48]
+ ldp x23, x24, [sp, #64]
+ ldp x25, x26, [sp, #80]
+ ldp x27, x28, [sp, #96]
+ ldp x29, x30, [sp], #112
+ ret
+SYM_CODE_END(__efi_rt_asm_recover)
diff --git a/arch/arm64/kernel/efi.c b/arch/arm64/kernel/efi.c
index a908a37f0367..fab05de2e12d 100644
--- a/arch/arm64/kernel/efi.c
+++ b/arch/arm64/kernel/efi.c
@@ -144,3 +144,52 @@ asmlinkage efi_status_t efi_handle_corrupted_x18(efi_status_t s, const char *f)
pr_err_ratelimited(FW_BUG "register x18 corrupted by EFI %s\n", f);
return s;
}
+
+DEFINE_SPINLOCK(efi_rt_lock);
+
+asmlinkage u64 *efi_rt_stack_top __ro_after_init;
+
+asmlinkage efi_status_t __efi_rt_asm_recover(void);
+
+bool efi_runtime_fixup_exception(struct pt_regs *regs, const char *msg)
+{
+ /* Check whether the exception occurred while running the firmware */
+ if (current_work() != &efi_rts_work.work || regs->pc >= TASK_SIZE_64)
+ return false;
+
+ pr_err(FW_BUG "Unable to handle %s in EFI runtime service\n", msg);
+ add_taint(TAINT_FIRMWARE_WORKAROUND, LOCKDEP_STILL_OK);
+ clear_bit(EFI_RUNTIME_SERVICES, &efi.flags);
+
+ regs->regs[0] = EFI_ABORTED;
+ regs->regs[30] = efi_rt_stack_top[-1];
+ regs->pc = (u64)__efi_rt_asm_recover;
+
+ if (IS_ENABLED(CONFIG_SHADOW_CALL_STACK))
+ regs->regs[18] = efi_rt_stack_top[-2];
+
+ return true;
+}
+
+/* EFI requires 8 KiB of stack space for runtime services */
+static_assert(THREAD_SIZE >= SZ_8K);
+
+static int __init arm64_efi_rt_init(void)
+{
+ void *p;
+
+ if (!efi_enabled(EFI_RUNTIME_SERVICES))
+ return 0;
+
+ p = __vmalloc_node(THREAD_SIZE, THREAD_ALIGN, GFP_KERNEL,
+ NUMA_NO_NODE, &&l);
+l: if (!p) {
+ pr_warn("Failed to allocate EFI runtime stack\n");
+ clear_bit(EFI_RUNTIME_SERVICES, &efi.flags);
+ return -ENOMEM;
+ }
+
+ efi_rt_stack_top = p + THREAD_SIZE;
+ return 0;
+}
+core_initcall(arm64_efi_rt_init);
diff --git a/arch/arm64/kernel/image-vars.h b/arch/arm64/kernel/image-vars.h
index 8151412653de..f31130ba0233 100644
--- a/arch/arm64/kernel/image-vars.h
+++ b/arch/arm64/kernel/image-vars.h
@@ -10,7 +10,6 @@
#error This file should only be included in vmlinux.lds.S
#endif
-PROVIDE(__efistub_kernel_size = _edata - _text);
PROVIDE(__efistub_primary_entry_offset = primary_entry - _text);
/*
@@ -22,13 +21,6 @@ PROVIDE(__efistub_primary_entry_offset = primary_entry - _text);
* linked at. The routines below are all implemented in assembler in a
* position independent manner
*/
-PROVIDE(__efistub_memcmp = __pi_memcmp);
-PROVIDE(__efistub_memchr = __pi_memchr);
-PROVIDE(__efistub_strlen = __pi_strlen);
-PROVIDE(__efistub_strnlen = __pi_strnlen);
-PROVIDE(__efistub_strcmp = __pi_strcmp);
-PROVIDE(__efistub_strncmp = __pi_strncmp);
-PROVIDE(__efistub_strrchr = __pi_strrchr);
PROVIDE(__efistub_dcache_clean_poc = __pi_dcache_clean_poc);
PROVIDE(__efistub__text = _text);
diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
index 74f76514a48d..3eb2825d08cf 100644
--- a/arch/arm64/mm/fault.c
+++ b/arch/arm64/mm/fault.c
@@ -30,6 +30,7 @@
#include <asm/bug.h>
#include <asm/cmpxchg.h>
#include <asm/cpufeature.h>
+#include <asm/efi.h>
#include <asm/exception.h>
#include <asm/daifflags.h>
#include <asm/debug-monitors.h>
@@ -397,6 +398,9 @@ static void __do_kernel_fault(unsigned long addr, unsigned long esr,
msg = "paging request";
}
+ if (efi_runtime_fixup_exception(regs, msg))
+ return;
+
die_kernel_fault(msg, addr, esr, regs);
}