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| author | Kirill A. Shutemov <kirill@shutemov.name> | 2021-11-30 21:49:31 +0300 |
|---|---|---|
| committer | Dave Hansen <dave.hansen@linux.intel.com> | 2021-11-30 14:53:04 -0800 |
| commit | d5ec1877df6da6a14bbc353aff50689528930dd2 (patch) | |
| tree | a5e6b273c022191205ade9be185fa33e83b97b3d /arch/x86/lib/insn-eval.c | |
| parent | 23ef731e4365196bfc186358eb4f6265d60ab352 (diff) | |
| download | lwn-d5ec1877df6da6a14bbc353aff50689528930dd2.tar.gz lwn-d5ec1877df6da6a14bbc353aff50689528930dd2.zip | |
x86/insn-eval: Introduce insn_get_modrm_reg_ptr()
The helper returns a pointer to the register indicated by
ModRM byte.
It's going to replace vc_insn_get_reg() in the SEV MMIO
implementation. TDX MMIO implementation will also use it.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Andi Kleen <ak@linux.intel.com>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Tested-by: Joerg Roedel <jroedel@suse.de>
Acked-by: Tom Lendacky <thomas.lendacky@amd.com>
Link: https://lkml.kernel.org/r/20211130184933.31005-3-kirill.shutemov@linux.intel.com
Diffstat (limited to 'arch/x86/lib/insn-eval.c')
| -rw-r--r-- | arch/x86/lib/insn-eval.c | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/arch/x86/lib/insn-eval.c b/arch/x86/lib/insn-eval.c index 1c51e8a415e2..8df6236e441c 100644 --- a/arch/x86/lib/insn-eval.c +++ b/arch/x86/lib/insn-eval.c @@ -849,6 +849,26 @@ int insn_get_modrm_reg_off(struct insn *insn, struct pt_regs *regs) } /** + * insn_get_modrm_reg_ptr() - Obtain register pointer based on ModRM byte + * @insn: Instruction containing the ModRM byte + * @regs: Register values as seen when entering kernel mode + * + * Returns: + * + * The register indicated by the reg part of the ModRM byte. + * The register is obtained as a pointer within pt_regs. + */ +unsigned long *insn_get_modrm_reg_ptr(struct insn *insn, struct pt_regs *regs) +{ + int offset; + + offset = insn_get_modrm_reg_off(insn, regs); + if (offset < 0) + return NULL; + return (void *)regs + offset; +} + +/** * get_seg_base_limit() - obtain base address and limit of a segment * @insn: Instruction. Must be valid. * @regs: Register values as seen when entering kernel mode |