redonkable/alistair23-linux
redonkable/alistair23-linux
1
0
Fork 0
Code Releases Activity

x86, efi: 1:1 pagetable mapping for virtual EFI calls

Browse source 
Some firmware still needs a 1:1 (virt->phys) mapping even after we've
called SetVirtualAddressMap(). So install the mapping alongside our
existing kernel mapping whenever we make EFI calls in virtual mode.

This bug was discovered on ASUS machines where the firmware
implementation of GetTime() accesses the RTC device via physical
addresses, even though that's bogus per the UEFI spec since we've
informed the firmware via SetVirtualAddressMap() that the boottime
memory map is no longer valid.

This bug seems to be present in a lot of consumer devices, so there's
not a lot we can do about this spec violation apart from workaround
it.

Cc: JérômeCarretero <cJ-ko@zougloub.eu>
Cc: Vasco Dias <rafa.vasco@gmail.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
This commit is contained in:
Matt Fleming 2012-09-07 18:28:04 +01:00
parent 53b87cf088
commit 185034e72d
2 changed files with 36 additions and 7 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

28
arch/x86/include/asm/efi.h
View file

@ -69,23 +69,37 @@ extern u64 efi_call6(void *fp, u64 arg1, u64 arg2, u64 arg3,
efi_call6((void *)(f), (u64)(a1), (u64)(a2), (u64)(a3), \
(u64)(a4), (u64)(a5), (u64)(a6))
extern unsigned long efi_call_virt_prelog(void);
extern void efi_call_virt_epilog(unsigned long);
#define efi_callx(x, func, ...) \
({ \
efi_status_t __status; \
unsigned long __pgd; \
\
__pgd = efi_call_virt_prelog(); \
__status = efi_call##x(func, __VA_ARGS__); \
efi_call_virt_epilog(__pgd); \
__status; \
})
#define efi_call_virt0(f) \
efi_call0((void *)(efi.systab->runtime->f))
efi_callx(0, (void *)(efi.systab->runtime->f))
#define efi_call_virt1(f, a1) \
efi_call1((void *)(efi.systab->runtime->f), (u64)(a1))
efi_callx(1, (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))
efi_callx(2, (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), \
efi_callx(3, (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), \
efi_callx(4, (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), \
efi_callx(5, (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), \
efi_callx(6, (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,

15
arch/x86/platform/efi/efi_64.c
View file

@ -58,6 +58,21 @@ static void __init early_code_mapping_set_exec(int executable)
}
}
unsigned long efi_call_virt_prelog(void)
{
unsigned long saved;
saved = read_cr3();
write_cr3(real_mode_header->trampoline_pgd);
return saved;
}
void efi_call_virt_epilog(unsigned long saved)
{
write_cr3(saved);
}
void __init efi_call_phys_prelog(void)
{
unsigned long vaddress;