Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
Merge tag 'efi-fixes-for-v6.1-4' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi
Pull EFI fix from Ard Biesheuvel:
"A single revert for some code that I added during this cycle. The code
is not wrong, but it should be a bit more careful about how to handle
the shadow call stack pointer, so it is better to revert it for now
and bring it back later in improved form.
Summary:
- Revert runtime service sync exception recovery on arm64"
* tag 'efi-fixes-for-v6.1-4' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi:
arm64: efi: Revert "Recover from synchronous exceptions ..."
+2
-69
-8
arch/arm64/include/asm/efi.h
-8
arch/arm64/include/asm/efi.h
···
14
14
15
15
#ifdef CONFIG_EFI
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extern void efi_init(void);
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-
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-
bool efi_runtime_fixup_exception(struct pt_regs *regs, const char *msg);
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#else
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#define efi_init()
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-
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static inline
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bool efi_runtime_fixup_exception(struct pt_regs *regs, const char *msg)
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-
{
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return false;
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-
}
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#endif
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int efi_create_mapping(struct mm_struct *mm, efi_memory_desc_t *md);
+2
-31
arch/arm64/kernel/efi-rt-wrapper.S
+2
-31
arch/arm64/kernel/efi-rt-wrapper.S
···
6
6
#include <linux/linkage.h>
7
7
8
8
SYM_FUNC_START(__efi_rt_asm_wrapper)
9
-
stp x29, x30, [sp, #-112]!
9
+
stp x29, x30, [sp, #-32]!
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mov x29, sp
11
11
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/*
···
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* (such as UEFI) should never touch it.
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*/
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stp x1, x18, [sp, #16]
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-
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/*
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* Preserve all callee saved registers and record the stack pointer
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* value in a per-CPU variable so we can recover from synchronous
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* exceptions occurring while running the firmware routines.
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*/
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stp x19, x20, [sp, #32]
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stp x21, x22, [sp, #48]
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stp x23, x24, [sp, #64]
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stp x25, x26, [sp, #80]
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stp x27, x28, [sp, #96]
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-
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adr_this_cpu x8, __efi_rt_asm_recover_sp, x9
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str x29, [x8]
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18
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/*
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20
* We are lucky enough that no EFI runtime services take more than
···
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45
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ldp x1, x2, [sp, #16]
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cmp x2, x18
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-
ldp x29, x30, [sp], #112
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+
ldp x29, x30, [sp], #32
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b.ne 0f
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ret
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0:
···
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mov x18, x2
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b efi_handle_corrupted_x18 // tail call
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SYM_FUNC_END(__efi_rt_asm_wrapper)
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-
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-
SYM_FUNC_START(__efi_rt_asm_recover)
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ldr_this_cpu x8, __efi_rt_asm_recover_sp, x9
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mov sp, x8
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-
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ldp x0, x18, [sp, #16]
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ldp x19, x20, [sp, #32]
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ldp x21, x22, [sp, #48]
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ldp x23, x24, [sp, #64]
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ldp x25, x26, [sp, #80]
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ldp x27, x28, [sp, #96]
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ldp x29, x30, [sp], #112
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-
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b efi_handle_runtime_exception
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SYM_FUNC_END(__efi_rt_asm_recover)
-26
arch/arm64/kernel/efi.c
-26
arch/arm64/kernel/efi.c
···
9
9
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#include <linux/efi.h>
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#include <linux/init.h>
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-
#include <linux/percpu.h>
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#include <asm/efi.h>
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14
···
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{
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pr_err_ratelimited(FW_BUG "register x18 corrupted by EFI %s\n", f);
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return s;
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-
}
147
-
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-
asmlinkage DEFINE_PER_CPU(u64, __efi_rt_asm_recover_sp);
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-
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asmlinkage efi_status_t __efi_rt_asm_recover(void);
151
-
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asmlinkage efi_status_t efi_handle_runtime_exception(const char *f)
153
-
{
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pr_err(FW_BUG "Synchronous exception occurred in EFI runtime service %s()\n", f);
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clear_bit(EFI_RUNTIME_SERVICES, &efi.flags);
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return EFI_ABORTED;
157
-
}
158
-
159
-
bool efi_runtime_fixup_exception(struct pt_regs *regs, const char *msg)
160
-
{
161
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/* Check whether the exception occurred while running the firmware */
162
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if (current_work() != &efi_rts_work.work || regs->pc >= TASK_SIZE_64)
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return false;
164
-
165
-
pr_err(FW_BUG "Unable to handle %s in EFI runtime service\n", msg);
166
-
add_taint(TAINT_FIRMWARE_WORKAROUND, LOCKDEP_STILL_OK);
167
-
dump_stack();
168
-
169
-
regs->pc = (u64)__efi_rt_asm_recover;
170
-
return true;
171
147
}
-4
arch/arm64/mm/fault.c
-4
arch/arm64/mm/fault.c
···
30
30
#include <asm/bug.h>
31
31
#include <asm/cmpxchg.h>
32
32
#include <asm/cpufeature.h>
33
-
#include <asm/efi.h>
34
33
#include <asm/exception.h>
35
34
#include <asm/daifflags.h>
36
35
#include <asm/debug-monitors.h>
···
390
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391
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msg = "paging request";
392
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}
393
-
394
-
if (efi_runtime_fixup_exception(regs, msg))
395
-
return;
396
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397
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die_kernel_fault(msg, addr, esr, regs);
398
396
}