Le 18/04/2022 à 09:38, Naveen N. Rao a écrit : > 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.le...@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?
Isn't there a risk of confusing with the 'li' instruction ? Like we could have PPC_INST_LI just like we have PPC_INST_ADD ? > >> + >> /* 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 It's not really just an instruction, it's closely linked to the ABI, so does it really belong to ppc-opcode.h ? Maybe it could be better to have it in ppc_asm.h instead, which already contains ABI related definitions ? If we move it into ppc-opcode.h, then we also have to move R2_STACK_OFFSET. Or should we use STK_GOT defined in ppc_asm.h and drop R2_STACK_OFFSET ? > >> 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. > Oops. Christophe