diff options
| author | Peter Zijlstra <peterz@infradead.org> | 2021-11-10 11:01:09 +0100 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2021-12-11 09:09:46 +0100 |
| commit | 4b5305decc8436bfe363d1c1773e8fa1c828b14d (patch) | |
| tree | 44e15c683e80d0043af001e0dec2425575cc09b9 /arch/x86/include/asm/extable_fixup_types.h | |
| parent | aa93e2ad7464ffb90155a5ffdde963816f86d5dc (diff) | |
x86/extable: Extend extable functionality
In order to remove further .fixup usage, extend the extable
infrastructure to take additional information from the extable entry
sites.
Specifically add _ASM_EXTABLE_TYPE_REG() and EX_TYPE_IMM_REG that
extend the existing _ASM_EXTABLE_TYPE() by taking an additional
register argument and encoding that and an s16 immediate into the
existing s32 type field. This limits the actual types to the first
byte, 255 seem plenty.
Also add a few flags into the type word, specifically CLEAR_AX and
CLEAR_DX which clear the return and extended return register.
Notes:
- due to the % in our register names it's hard to make it more
generally usable as arm64 did.
- the s16 is far larger than used in these patches, future extentions
can easily shrink this to get more bits.
- without the bitfield fix this will not compile, because: 0xFF > -1
and we can't even extract the TYPE field.
[nathanchance: Build fix for clang-lto builds:
https://lkml.kernel.org/r/20211210234953.3420108-1-nathan@kernel.org
]
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Link: https://lore.kernel.org/r/20211110101325.303890153@infradead.org
Diffstat (limited to 'arch/x86/include/asm/extable_fixup_types.h')
| -rw-r--r-- | arch/x86/include/asm/extable_fixup_types.h | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/arch/x86/include/asm/extable_fixup_types.h b/arch/x86/include/asm/extable_fixup_types.h index 4d709a2768bb..944f8329022a 100644 --- a/arch/x86/include/asm/extable_fixup_types.h +++ b/arch/x86/include/asm/extable_fixup_types.h @@ -2,6 +2,29 @@ #ifndef _ASM_X86_EXTABLE_FIXUP_TYPES_H #define _ASM_X86_EXTABLE_FIXUP_TYPES_H +/* + * Our IMM is signed, as such it must live at the top end of the word. Also, + * since C99 hex constants are of ambigious type, force cast the mask to 'int' + * so that FIELD_GET() will DTRT and sign extend the value when it extracts it. + */ +#define EX_DATA_TYPE_MASK ((int)0x000000FF) +#define EX_DATA_REG_MASK ((int)0x00000F00) +#define EX_DATA_FLAG_MASK ((int)0x0000F000) +#define EX_DATA_IMM_MASK ((int)0xFFFF0000) + +#define EX_DATA_REG_SHIFT 8 +#define EX_DATA_FLAG_SHIFT 12 +#define EX_DATA_IMM_SHIFT 16 + +#define EX_DATA_FLAG(flag) ((flag) << EX_DATA_FLAG_SHIFT) +#define EX_DATA_IMM(imm) ((imm) << EX_DATA_IMM_SHIFT) + +/* flags */ +#define EX_FLAG_CLEAR_AX EX_DATA_FLAG(1) +#define EX_FLAG_CLEAR_DX EX_DATA_FLAG(2) +#define EX_FLAG_CLEAR_AX_DX EX_DATA_FLAG(3) + +/* types */ #define EX_TYPE_NONE 0 #define EX_TYPE_DEFAULT 1 #define EX_TYPE_FAULT 2 @@ -20,5 +43,6 @@ #define EX_TYPE_FAULT_MCE_SAFE 13 #define EX_TYPE_POP_ZERO 14 +#define EX_TYPE_IMM_REG 15 /* reg := (long)imm */ #endif |