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SubjectRe: [PATCH v1 13/22] powerpc/ftrace: Use PPC_RAW_xxx() macros instead of opencoding.
Christophe Leroy wrote:
> PPC_RAW_xxx() macros are self explanatory and less error prone
> than open coding.
>
> Use them in ftrace.c
>
> Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
> ---
> arch/powerpc/include/asm/ppc-opcode.h | 3 +++
> arch/powerpc/kernel/trace/ftrace.c | 32 +++++++++------------------
> 2 files changed, 14 insertions(+), 21 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/ppc-opcode.h b/arch/powerpc/include/asm/ppc-opcode.h
> index 82f1f0041c6f..281754aca0a3 100644
> --- a/arch/powerpc/include/asm/ppc-opcode.h
> +++ b/arch/powerpc/include/asm/ppc-opcode.h
> @@ -294,6 +294,8 @@
> #define PPC_INST_BL 0x48000001
> #define PPC_INST_BRANCH_COND 0x40800000
>
> +#define PPC_INST_OFFSET24_MASK 0x03fffffc

This corresponds to the LI field, per the ISA. See section 8.1.2/1.7:
'Instruction Fields'. Would it be better to name it PPC_INST_LI_MASK?

> +
> /* Prefixes */
> #define PPC_INST_LFS 0xc0000000
> #define PPC_INST_STFS 0xd0000000
> @@ -572,6 +574,7 @@
> #define PPC_RAW_EIEIO() (0x7c0006ac)
>
> #define PPC_RAW_BRANCH(addr) (PPC_INST_BRANCH | ((addr) & 0x03fffffc))
> +#define PPC_RAW_BL(offset) (0x48000001 | ((offset) & PPC_INST_OFFSET24_MASK))
>
> /* Deal with instructions that older assemblers aren't aware of */
> #define PPC_BCCTR_FLUSH stringify_in_c(.long PPC_INST_BCCTR_FLUSH)
> diff --git a/arch/powerpc/kernel/trace/ftrace.c b/arch/powerpc/kernel/trace/ftrace.c
> index fdc0412c1d8a..afb1d12838c9 100644
> --- a/arch/powerpc/kernel/trace/ftrace.c
> +++ b/arch/powerpc/kernel/trace/ftrace.c
> @@ -90,19 +90,19 @@ static int test_24bit_addr(unsigned long ip, unsigned long addr)
>
> static int is_bl_op(ppc_inst_t op)
> {
> - return (ppc_inst_val(op) & 0xfc000003) == 0x48000001;
> + return (ppc_inst_val(op) & ~PPC_INST_OFFSET24_MASK) == PPC_RAW_BL(0);
> }
>
> static int is_b_op(ppc_inst_t op)
> {
> - return (ppc_inst_val(op) & 0xfc000003) == 0x48000000;
> + return (ppc_inst_val(op) & ~PPC_INST_OFFSET24_MASK) == PPC_RAW_BRANCH(0);
> }
>
> static unsigned long find_bl_target(unsigned long ip, ppc_inst_t op)
> {
> int offset;
>
> - offset = (ppc_inst_val(op) & 0x03fffffc);
> + offset = (ppc_inst_val(op) & PPC_INST_OFFSET24_MASK);
> /* make it signed */
> if (offset & 0x02000000)
> offset |= 0xfe000000;
> @@ -182,7 +182,7 @@ __ftrace_make_nop(struct module *mod,
> * Use a b +8 to jump over the load.
> */
>
> - pop = ppc_inst(PPC_INST_BRANCH | 8); /* b +8 */
> + pop = ppc_inst(PPC_RAW_BRANCH(8)); /* b +8 */
>
> /*
> * Check what is in the next instruction. We can see ld r2,40(r1), but
> @@ -394,17 +394,8 @@ int ftrace_make_nop(struct module *mod,
> static int
> expected_nop_sequence(void *ip, ppc_inst_t op0, ppc_inst_t op1)
> {
> - /*
> - * We expect to see:
> - *
> - * b +8
> - * ld r2,XX(r1)
> - *
> - * The load offset is different depending on the ABI. For simplicity
> - * just mask it out when doing the compare.
> - */
> - if (!ppc_inst_equal(op0, ppc_inst(0x48000008)) ||
> - (ppc_inst_val(op1) & 0xffff0000) != 0xe8410000)
> + if (!ppc_inst_equal(op0, ppc_inst(PPC_RAW_BRANCH(8))) ||
> + !ppc_inst_equal(op1, ppc_inst(PPC_INST_LD_TOC)))

It would be good to move PPC_INST_LD_TOC to ppc-opcode.h

> return 0;
> return 1;
> }
> @@ -412,7 +403,6 @@ expected_nop_sequence(void *ip, ppc_inst_t op0, ppc_inst_t op1)
> static int
> expected_nop_sequence(void *ip, ppc_inst_t op0, ppc_inst_t op1)
> {
> - /* look for patched "NOP" on ppc64 with -mprofile-kernel or ppc32 */
> if (!ppc_inst_equal(op0, ppc_inst(PPC_RAW_NOP())))
> return 0;
> return 1;
> @@ -738,11 +728,11 @@ int __init ftrace_dyn_arch_init(void)
> int i;
> unsigned int *tramp[] = { ftrace_tramp_text, ftrace_tramp_init };
> u32 stub_insns[] = {
> - 0xe98d0000 | PACATOC, /* ld r12,PACATOC(r13) */
> - 0x3d8c0000, /* addis r12,r12,<high> */
> - 0x398c0000, /* addi r12,r12,<low> */
> - 0x7d8903a6, /* mtctr r12 */
> - 0x4e800420, /* bctr */
> + PPC_RAW_LD(_R12, _R13, PACATOC),
> + PPC_RAW_ADDIS(_R12, _R12, 0),
> + PPC_RAW_ADDIS(_R12, _R12, 0),

This should be PPC_RAW_ADDI.


- Naveen

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