alistair23-linux/arch/x86/include/asm/efi.h
Matthew Garrett f8b8404337 Modify UEFI anti-bricking code
This patch reworks the UEFI anti-bricking code, including an effective
reversion of cc5a080c and 31ff2f20. It turns out that calling
QueryVariableInfo() from boot services results in some firmware
implementations jumping to physical addresses even after entering virtual
mode, so until we have 1:1 mappings for UEFI runtime space this isn't
going to work so well.

Reverting these gets us back to the situation where we'd refuse to create
variables on some systems because they classify deleted variables as "used"
until the firmware triggers a garbage collection run, which they won't do
until they reach a lower threshold. This results in it being impossible to
install a bootloader, which is unhelpful.

Feedback from Samsung indicates that the firmware doesn't need more than
5KB of storage space for its own purposes, so that seems like a reasonable
threshold. However, there's still no guarantee that a platform will attempt
garbage collection merely because it drops below this threshold. It seems
that this is often only triggered if an attempt to write generates a
genuine EFI_OUT_OF_RESOURCES error. We can force that by attempting to
create a variable larger than the remaining space. This should fail, but if
it somehow succeeds we can then immediately delete it.

I've tested this on the UEFI machines I have available, but I don't have
a Samsung and so can't verify that it avoids the bricking problem.

Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com>
Signed-off-by: Lee, Chun-Y <jlee@suse.com> [ dummy variable cleanup ]
Cc: <stable@vger.kernel.org>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
2013-06-10 21:59:37 +01:00

126 lines
4.5 KiB
C

#ifndef _ASM_X86_EFI_H
#define _ASM_X86_EFI_H
#ifdef CONFIG_X86_32
#define EFI_LOADER_SIGNATURE "EL32"
extern unsigned long asmlinkage efi_call_phys(void *, ...);
#define efi_call_phys0(f) efi_call_phys(f)
#define efi_call_phys1(f, a1) efi_call_phys(f, a1)
#define efi_call_phys2(f, a1, a2) efi_call_phys(f, a1, a2)
#define efi_call_phys3(f, a1, a2, a3) efi_call_phys(f, a1, a2, a3)
#define efi_call_phys4(f, a1, a2, a3, a4) \
efi_call_phys(f, a1, a2, a3, a4)
#define efi_call_phys5(f, a1, a2, a3, a4, a5) \
efi_call_phys(f, a1, a2, a3, a4, a5)
#define efi_call_phys6(f, a1, a2, a3, a4, a5, a6) \
efi_call_phys(f, a1, a2, a3, a4, a5, a6)
/*
* Wrap all the virtual calls in a way that forces the parameters on the stack.
*/
#define efi_call_virt(f, args...) \
((efi_##f##_t __attribute__((regparm(0)))*)efi.systab->runtime->f)(args)
#define efi_call_virt0(f) efi_call_virt(f)
#define efi_call_virt1(f, a1) efi_call_virt(f, a1)
#define efi_call_virt2(f, a1, a2) efi_call_virt(f, a1, a2)
#define efi_call_virt3(f, a1, a2, a3) efi_call_virt(f, a1, a2, a3)
#define efi_call_virt4(f, a1, a2, a3, a4) \
efi_call_virt(f, a1, a2, a3, a4)
#define efi_call_virt5(f, a1, a2, a3, a4, a5) \
efi_call_virt(f, a1, a2, a3, a4, a5)
#define efi_call_virt6(f, a1, a2, a3, a4, a5, a6) \
efi_call_virt(f, a1, a2, a3, a4, a5, a6)
#define efi_ioremap(addr, size, type, attr) ioremap_cache(addr, size)
#else /* !CONFIG_X86_32 */
#define EFI_LOADER_SIGNATURE "EL64"
extern u64 efi_call0(void *fp);
extern u64 efi_call1(void *fp, u64 arg1);
extern u64 efi_call2(void *fp, u64 arg1, u64 arg2);
extern u64 efi_call3(void *fp, u64 arg1, u64 arg2, u64 arg3);
extern u64 efi_call4(void *fp, u64 arg1, u64 arg2, u64 arg3, u64 arg4);
extern u64 efi_call5(void *fp, u64 arg1, u64 arg2, u64 arg3,
u64 arg4, u64 arg5);
extern u64 efi_call6(void *fp, u64 arg1, u64 arg2, u64 arg3,
u64 arg4, u64 arg5, u64 arg6);
#define efi_call_phys0(f) \
efi_call0((void *)(f))
#define efi_call_phys1(f, a1) \
efi_call1((void *)(f), (u64)(a1))
#define efi_call_phys2(f, a1, a2) \
efi_call2((void *)(f), (u64)(a1), (u64)(a2))
#define efi_call_phys3(f, a1, a2, a3) \
efi_call3((void *)(f), (u64)(a1), (u64)(a2), (u64)(a3))
#define efi_call_phys4(f, a1, a2, a3, a4) \
efi_call4((void *)(f), (u64)(a1), (u64)(a2), (u64)(a3), \
(u64)(a4))
#define efi_call_phys5(f, a1, a2, a3, a4, a5) \
efi_call5((void *)(f), (u64)(a1), (u64)(a2), (u64)(a3), \
(u64)(a4), (u64)(a5))
#define efi_call_phys6(f, a1, a2, a3, a4, a5, a6) \
efi_call6((void *)(f), (u64)(a1), (u64)(a2), (u64)(a3), \
(u64)(a4), (u64)(a5), (u64)(a6))
#define efi_call_virt0(f) \
efi_call0((void *)(efi.systab->runtime->f))
#define efi_call_virt1(f, a1) \
efi_call1((void *)(efi.systab->runtime->f), (u64)(a1))
#define efi_call_virt2(f, a1, a2) \
efi_call2((void *)(efi.systab->runtime->f), (u64)(a1), (u64)(a2))
#define efi_call_virt3(f, a1, a2, a3) \
efi_call3((void *)(efi.systab->runtime->f), (u64)(a1), (u64)(a2), \
(u64)(a3))
#define efi_call_virt4(f, a1, a2, a3, a4) \
efi_call4((void *)(efi.systab->runtime->f), (u64)(a1), (u64)(a2), \
(u64)(a3), (u64)(a4))
#define efi_call_virt5(f, a1, a2, a3, a4, a5) \
efi_call5((void *)(efi.systab->runtime->f), (u64)(a1), (u64)(a2), \
(u64)(a3), (u64)(a4), (u64)(a5))
#define efi_call_virt6(f, a1, a2, a3, a4, a5, a6) \
efi_call6((void *)(efi.systab->runtime->f), (u64)(a1), (u64)(a2), \
(u64)(a3), (u64)(a4), (u64)(a5), (u64)(a6))
extern void __iomem *efi_ioremap(unsigned long addr, unsigned long size,
u32 type, u64 attribute);
#endif /* CONFIG_X86_32 */
extern int add_efi_memmap;
extern unsigned long x86_efi_facility;
extern void efi_set_executable(efi_memory_desc_t *md, bool executable);
extern int efi_memblock_x86_reserve_range(void);
extern void efi_call_phys_prelog(void);
extern void efi_call_phys_epilog(void);
extern void efi_unmap_memmap(void);
extern void efi_memory_uc(u64 addr, unsigned long size);
#ifdef CONFIG_EFI
static inline bool efi_is_native(void)
{
return IS_ENABLED(CONFIG_X86_64) == efi_enabled(EFI_64BIT);
}
#else
/*
* IF EFI is not configured, have the EFI calls return -ENOSYS.
*/
#define efi_call0(_f) (-ENOSYS)
#define efi_call1(_f, _a1) (-ENOSYS)
#define efi_call2(_f, _a1, _a2) (-ENOSYS)
#define efi_call3(_f, _a1, _a2, _a3) (-ENOSYS)
#define efi_call4(_f, _a1, _a2, _a3, _a4) (-ENOSYS)
#define efi_call5(_f, _a1, _a2, _a3, _a4, _a5) (-ENOSYS)
#define efi_call6(_f, _a1, _a2, _a3, _a4, _a5, _a6) (-ENOSYS)
#endif /* CONFIG_EFI */
#endif /* _ASM_X86_EFI_H */