From 185034e72d591f9465e5e18f937ed642e7ea0070 Mon Sep 17 00:00:00 2001 From: Matt Fleming Date: Fri, 7 Sep 2012 18:28:04 +0100 Subject: x86, efi: 1:1 pagetable mapping for virtual EFI calls MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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bogus per the UEFI spec since we've informed the firmware via SetVirtualAddressMap() that the boottime memory map is no longer valid.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 Cc: Vasco Dias Acked-by: Jan Beulich Signed-off-by: Matt Fleming --- arch/x86/include/asm/efi.h | 28 +++++++++++++++++++++------- arch/x86/platform/efi/efi_64.c | 15 +++++++++++++++ 2 files changed, 36 insertions(+), 7 deletions(-) diff --git a/arch/x86/include/asm/efi.h b/arch/x86/include/asm/efi.h index c9dcc181d4d..ae3bf3b8da7 100644 --- a/arch/x86/include/asm/efi.h +++ b/arch/x86/include/asm/efi.h @@ -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, diff --git a/arch/x86/platform/efi/efi_64.c b/arch/x86/platform/efi/efi_64.c index ac3aa54e265..ddb0174cf09 100644 --- a/arch/x86/platform/efi/efi_64.c +++ b/arch/x86/platform/efi/efi_64.c @@ -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; -- cgit v1.2.3-70-g09d2