69c0b12578
In order to be able to cope with kernel-mode NEON being unavailable
in hardirq/nmi context and non-nestable, we need special handling
for EFI runtime service calls that may be made during an interrupt
that interrupted a kernel_neon_begin()..._end() block. This will
occur if the kernel tries to write diagnostic data to EFI
persistent storage during a panic triggered by an NMI for example.
EFI runtime services specify an ABI that clobbers the FPSIMD state,
rather than being able to use it optionally as an accelerator.
This means that EFI is really a special case and can be handled
specially.
To enable EFI calls from interrupts, this patch creates dedicated
__efi_fpsimd_{begin,end}() helpers solely for this purpose, which
save/restore to a separate percpu buffer if called in a context
where kernel_neon_begin() is not usable.
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
117 lines
3.3 KiB
C
117 lines
3.3 KiB
C
#ifndef _ASM_EFI_H
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#define _ASM_EFI_H
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#include <asm/cpufeature.h>
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#include <asm/fpsimd.h>
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#include <asm/io.h>
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#include <asm/mmu_context.h>
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#include <asm/neon.h>
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#include <asm/ptrace.h>
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#include <asm/tlbflush.h>
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#ifdef CONFIG_EFI
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extern void efi_init(void);
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#else
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#define efi_init()
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#endif
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int efi_create_mapping(struct mm_struct *mm, efi_memory_desc_t *md);
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int efi_set_mapping_permissions(struct mm_struct *mm, efi_memory_desc_t *md);
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#define arch_efi_call_virt_setup() \
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({ \
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efi_virtmap_load(); \
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__efi_fpsimd_begin(); \
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})
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#define arch_efi_call_virt(p, f, args...) \
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({ \
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efi_##f##_t *__f; \
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__f = p->f; \
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__f(args); \
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})
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#define arch_efi_call_virt_teardown() \
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({ \
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__efi_fpsimd_end(); \
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efi_virtmap_unload(); \
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})
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#define ARCH_EFI_IRQ_FLAGS_MASK (PSR_D_BIT | PSR_A_BIT | PSR_I_BIT | PSR_F_BIT)
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/* arch specific definitions used by the stub code */
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/*
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* AArch64 requires the DTB to be 8-byte aligned in the first 512MiB from
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* start of kernel and may not cross a 2MiB boundary. We set alignment to
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* 2MiB so we know it won't cross a 2MiB boundary.
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*/
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#define EFI_FDT_ALIGN SZ_2M /* used by allocate_new_fdt_and_exit_boot() */
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#define MAX_FDT_OFFSET SZ_512M
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#define efi_call_early(f, ...) sys_table_arg->boottime->f(__VA_ARGS__)
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#define __efi_call_early(f, ...) f(__VA_ARGS__)
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#define efi_is_64bit() (true)
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#define alloc_screen_info(x...) &screen_info
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static inline void free_screen_info(efi_system_table_t *sys_table_arg,
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struct screen_info *si)
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{
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}
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/* redeclare as 'hidden' so the compiler will generate relative references */
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extern struct screen_info screen_info __attribute__((__visibility__("hidden")));
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static inline void efifb_setup_from_dmi(struct screen_info *si, const char *opt)
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{
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}
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#define EFI_ALLOC_ALIGN SZ_64K
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/*
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* On ARM systems, virtually remapped UEFI runtime services are set up in two
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* distinct stages:
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* - The stub retrieves the final version of the memory map from UEFI, populates
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* the virt_addr fields and calls the SetVirtualAddressMap() [SVAM] runtime
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* service to communicate the new mapping to the firmware (Note that the new
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* mapping is not live at this time)
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* - During an early initcall(), the EFI system table is permanently remapped
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* and the virtual remapping of the UEFI Runtime Services regions is loaded
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* into a private set of page tables. If this all succeeds, the Runtime
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* Services are enabled and the EFI_RUNTIME_SERVICES bit set.
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*/
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static inline void efi_set_pgd(struct mm_struct *mm)
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{
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__switch_mm(mm);
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if (system_uses_ttbr0_pan()) {
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if (mm != current->active_mm) {
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/*
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* Update the current thread's saved ttbr0 since it is
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* restored as part of a return from exception. Enable
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* access to the valid TTBR0_EL1 and invoke the errata
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* workaround directly since there is no return from
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* exception when invoking the EFI run-time services.
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*/
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update_saved_ttbr0(current, mm);
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uaccess_ttbr0_enable();
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post_ttbr_update_workaround();
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} else {
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/*
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* Defer the switch to the current thread's TTBR0_EL1
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* until uaccess_enable(). Restore the current
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* thread's saved ttbr0 corresponding to its active_mm
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*/
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uaccess_ttbr0_disable();
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update_saved_ttbr0(current, current->active_mm);
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}
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}
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}
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void efi_virtmap_load(void);
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void efi_virtmap_unload(void);
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#endif /* _ASM_EFI_H */
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