Messages in this thread Patch in this message | | | From | Sukadev Bhattiprolu <> | Subject | [PATCH 02/10][v6] powerpc/Power7: detect load/store instructions | Date | Tue, 15 Oct 2013 19:06:34 -0700 |
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Implement instr_is_load_store_2_06() to detect whether a given instruction is one of the fixed-point or floating-point load/store instructions in the POWER Instruction Set Architecture v2.06.
This function will be used in a follow-on patch to save memory hierarchy information of the load/store on a Power7 system. (Power8 systems set some bits in the SIER to identify load/store operations and hence don't need a similar functionality).
Based on optimized code from Michael Ellerman and comments from Tom Musta.
Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com> --- Changelog[v6] - [Michael Ellerman, Tom Musta]: Optmize the implementation to avoid for loop.
arch/powerpc/include/asm/code-patching.h | 1 + arch/powerpc/lib/code-patching.c | 45 ++++++++++++++++++++++++++++++ 2 files changed, 46 insertions(+)
diff --git a/arch/powerpc/include/asm/code-patching.h b/arch/powerpc/include/asm/code-patching.h index a6f8c7a..9cc3ef1 100644 --- a/arch/powerpc/include/asm/code-patching.h +++ b/arch/powerpc/include/asm/code-patching.h @@ -34,6 +34,7 @@ int instr_is_branch_to_addr(const unsigned int *instr, unsigned long addr); unsigned long branch_target(const unsigned int *instr); unsigned int translate_branch(const unsigned int *dest, const unsigned int *src); +int instr_is_load_store_2_06(const unsigned int *instr); static inline unsigned long ppc_function_entry(void *func) { diff --git a/arch/powerpc/lib/code-patching.c b/arch/powerpc/lib/code-patching.c index 2bc9db3..49fb9d7 100644 --- a/arch/powerpc/lib/code-patching.c +++ b/arch/powerpc/lib/code-patching.c @@ -159,6 +159,51 @@ unsigned int translate_branch(const unsigned int *dest, const unsigned int *src) return 0; } +/* + * Determine if the op code in the instruction corresponds to a load or + * store instruction. Ignore the vector load instructions like evlddepx, + * evstddepx for now. + * + * This function is valid for POWER ISA 2.06. + * + * Reference: PowerISA_V2.06B_Public.pdf, Sections 3.3.2 through 3.3.6 + * and 4.6.2 through 4.6.4, Appendix F (Opcode Maps). + */ +int instr_is_load_store_2_06(const unsigned int *instr) +{ + unsigned int op, upper, lower; + + op = instr_opcode(*instr); + + if ((op >= 32 && op <= 58) || (op == 61 || op == 62)) + return true; + + if (op != 31) + return false; + + upper = op >> 5; + lower = op & 0x1f; + + /* Short circuit as many misses as we can */ + if (lower < 3 || lower > 23) + return false; + + if (lower == 3) { + if (upper >= 16) + return true; + + return false; + } + + if (lower == 7 || lower == 12) + return true; + + if (lower >= 20) /* && lower <= 23 (implicit) */ + return true; + + return false; +} + #ifdef CONFIG_CODE_PATCHING_SELFTEST -- 1.7.9.5
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