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x86/efi: Runtime services virtual mapping

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We map the EFI regions needed for runtime services non-contiguously,
with preserved alignment on virtual addresses starting from -4G down
for a total max space of 64G. This way, we provide for stable runtime
services addresses across kernels so that a kexec'd kernel can still use
them.

Thus, they're mapped in a separate pagetable so that we don't pollute
the kernel namespace.

Add an efi= kernel command line parameter for passing miscellaneous
options and chicken bits from the command line.

While at it, add a chicken bit called "efi=old_map" which can be used as
a fallback to the old runtime services mapping method in case there's
some b0rkage with a particular EFI implementation (haha, it is hard to
hold up the sarcasm here...).

Also, add the UEFI RT VA space to Documentation/x86/x86_64/mm.txt.

Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
This commit is contained in:
Borislav Petkov 2013-10-31 17:25:08 +01:00 • committed by Matt Fleming
parent 82f0712ca0
commit d2f7cbe7b2
9 changed files with 300 additions and 47 deletions
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64
arch/x86/include/asm/efi.h
View file

@ -1,6 +1,24 @@
#ifndef _ASM_X86_EFI_H
#define _ASM_X86_EFI_H
/*
* We map the EFI regions needed for runtime services non-contiguously,
* with preserved alignment on virtual addresses starting from -4G down
* for a total max space of 64G. This way, we provide for stable runtime
* services addresses across kernels so that a kexec'd kernel can still
* use them.
*
* This is the main reason why we're doing stable VA mappings for RT
* services.
*
* This flag is used in conjuction with a chicken bit called
* "efi=old_map" which can be used as a fallback to the old runtime
* services mapping method in case there's some b0rkage with a
* particular EFI implementation (haha, it is hard to hold up the
* sarcasm here...).
*/
#define EFI_OLD_MEMMAP EFI_ARCH_1
#ifdef CONFIG_X86_32
#define EFI_LOADER_SIGNATURE "EL32"
@ -69,24 +87,31 @@ extern u64 efi_call6(void *fp, u64 arg1, u64 arg2, u64 arg3,
efi_call6((f), (u64)(a1), (u64)(a2), (u64)(a3), \
(u64)(a4), (u64)(a5), (u64)(a6))
#define _efi_call_virtX(x, f, ...) \
({ \
efi_status_t __s; \
\
efi_sync_low_kernel_mappings(); \
preempt_disable(); \
__s = efi_call##x((void *)efi.systab->runtime->f, __VA_ARGS__); \
preempt_enable(); \
__s; \
})
#define efi_call_virt0(f) \
efi_call0((efi.systab->runtime->f))
#define efi_call_virt1(f, a1) \
efi_call1((efi.systab->runtime->f), (u64)(a1))
#define efi_call_virt2(f, a1, a2) \
efi_call2((efi.systab->runtime->f), (u64)(a1), (u64)(a2))
#define efi_call_virt3(f, a1, a2, a3) \
efi_call3((efi.systab->runtime->f), (u64)(a1), (u64)(a2), \
(u64)(a3))
#define efi_call_virt4(f, a1, a2, a3, a4) \
efi_call4((efi.systab->runtime->f), (u64)(a1), (u64)(a2), \
(u64)(a3), (u64)(a4))
#define efi_call_virt5(f, a1, a2, a3, a4, a5) \
efi_call5((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((efi.systab->runtime->f), (u64)(a1), (u64)(a2), \
(u64)(a3), (u64)(a4), (u64)(a5), (u64)(a6))
_efi_call_virtX(0, f)
#define efi_call_virt1(f, a1) \
_efi_call_virtX(1, f, (u64)(a1))
#define efi_call_virt2(f, a1, a2) \
_efi_call_virtX(2, f, (u64)(a1), (u64)(a2))
#define efi_call_virt3(f, a1, a2, a3) \
_efi_call_virtX(3, f, (u64)(a1), (u64)(a2), (u64)(a3))
#define efi_call_virt4(f, a1, a2, a3, a4) \
_efi_call_virtX(4, f, (u64)(a1), (u64)(a2), (u64)(a3), (u64)(a4))
#define efi_call_virt5(f, a1, a2, a3, a4, a5) \
_efi_call_virtX(5, f, (u64)(a1), (u64)(a2), (u64)(a3), (u64)(a4), (u64)(a5))
#define efi_call_virt6(f, a1, a2, a3, a4, a5, a6) \
_efi_call_virtX(6, 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);
@ -95,12 +120,17 @@ extern void __iomem *efi_ioremap(unsigned long addr, unsigned long size,
extern int add_efi_memmap;
extern unsigned long x86_efi_facility;
extern struct efi_scratch efi_scratch;
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);
extern void __init efi_map_region(efi_memory_desc_t *md);
extern void efi_sync_low_kernel_mappings(void);
extern void efi_setup_page_tables(void);
extern void __init old_map_region(efi_memory_desc_t *md);
#ifdef CONFIG_EFI