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arm64/efi: Move uaccess en/disable out of efi_set_pgd()

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efi_set_pgd() will no longer be called when invoking EFI runtime
services via the efi_rts_wq work queue, but the uaccess en/disable are
still needed when using PAN emulation using TTBR0 switching. So move
these into the callers.

Acked-by: Will Deacon <will@kernel.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This commit is contained in:
Ard Biesheuvel
2025-10-15 22:56:41 +02:00
committed by Catalin Marinas
parent 1068cb52e8
commit 6b9c98e657
2 changed files with 21 additions and 10 deletions
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13
arch/arm64/include/asm/efi.h
View File

@@ -126,21 +126,14 @@ static inline void efi_set_pgd(struct mm_struct *mm)
if (mm != current->active_mm) {
/*
* Update the current thread's saved ttbr0 since it is
* restored as part of a return from exception. Enable
* access to the valid TTBR0_EL1 and invoke the errata
* workaround directly since there is no return from
* exception when invoking the EFI run-time services.
* restored as part of a return from exception.
*/
update_saved_ttbr0(current, mm);
uaccess_ttbr0_enable();
post_ttbr_update_workaround();
} else {
/*
* Defer the switch to the current thread's TTBR0_EL1
* until uaccess_enable(). Restore the current
* thread's saved ttbr0 corresponding to its active_mm
* Restore the current thread's saved ttbr0
* corresponding to its active_mm
*/
uaccess_ttbr0_disable();
update_saved_ttbr0(current, current->active_mm);
}
}

18
arch/arm64/kernel/efi.c
View File

@@ -169,12 +169,30 @@ void arch_efi_call_virt_setup(void)
{
efi_runtime_assert_lock_held();
efi_virtmap_load();
/*
* Enable access to the valid TTBR0_EL1 and invoke the errata
* workaround directly since there is no return from exception when
* invoking the EFI run-time services.
*/
uaccess_ttbr0_enable();
post_ttbr_update_workaround();
__efi_fpsimd_begin();
}
void arch_efi_call_virt_teardown(void)
{
__efi_fpsimd_end();
/*
* Defer the switch to the current thread's TTBR0_EL1 until
* uaccess_enable(). Do so before efi_virtmap_unload() updates the
* saved TTBR0 value, so the userland page tables are not activated
* inadvertently over the back of an exception.
*/
uaccess_ttbr0_disable();
efi_virtmap_unload();
}