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 <suka...@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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