| Message ID | 1439254364-15362-3-git-send-email-dave.long@linaro.org |
|---|---|
| State | New |
| Headers | show |
On 08/11/15 14:00, Will Deacon wrote: > On Tue, Aug 11, 2015 at 01:52:39AM +0100, David Long wrote: >> From: "David A. Long" <dave.long@linaro.org> >> >> Certain instructions are hard to execute correctly out-of-line (as in >> kprobes). Test functions are added to insn.[hc] to identify these. The >> instructions include any that use PC-relative addressing, change the PC, >> or change interrupt masking. For efficiency and simplicity test >> functions are also added for small collections of related instructions. >> >> Signed-off-by: David A. Long <dave.long@linaro.org> >> --- >> arch/arm64/include/asm/insn.h | 18 ++++++++++++++++++ >> arch/arm64/kernel/insn.c | 28 ++++++++++++++++++++++++++++ >> 2 files changed, 46 insertions(+) >> >> diff --git a/arch/arm64/include/asm/insn.h b/arch/arm64/include/asm/insn.h >> index 30e50eb..66bfb21 100644 >> --- a/arch/arm64/include/asm/insn.h >> +++ b/arch/arm64/include/asm/insn.h >> @@ -223,8 +223,13 @@ static __always_inline bool aarch64_insn_is_##abbr(u32 code) \ >> static __always_inline u32 aarch64_insn_get_##abbr##_value(void) \ >> { return (val); } >> >> +__AARCH64_INSN_FUNCS(adr_adrp, 0x1F000000, 0x10000000) >> +__AARCH64_INSN_FUNCS(prfm_lit, 0xFF000000, 0xD8000000) >> __AARCH64_INSN_FUNCS(str_reg, 0x3FE0EC00, 0x38206800) >> __AARCH64_INSN_FUNCS(ldr_reg, 0x3FE0EC00, 0x38606800) >> +__AARCH64_INSN_FUNCS(ldr_lit, 0xBF000000, 0x18000000) >> +__AARCH64_INSN_FUNCS(ldrsw_lit, 0xFF000000, 0x98000000) >> +__AARCH64_INSN_FUNCS(exclusive, 0x3F000000, 0x08000000) > > Hmm, so this class also pulls in load-acquire and store-release, which > we *should* be able to single-step, no? Maybe it's worth splitting this > category up (or at least changing aarch64_insn_is_exclusive to be more > permissive). I was not confident that this was the case. After reading the relevant parts of the v8 ARM yet again I think I see your point. > >> __AARCH64_INSN_FUNCS(stp_post, 0x7FC00000, 0x28800000) >> __AARCH64_INSN_FUNCS(ldp_post, 0x7FC00000, 0x28C00000) >> __AARCH64_INSN_FUNCS(stp_pre, 0x7FC00000, 0x29800000) >> @@ -264,19 +269,29 @@ __AARCH64_INSN_FUNCS(ands, 0x7F200000, 0x6A000000) >> __AARCH64_INSN_FUNCS(bics, 0x7F200000, 0x6A200000) >> __AARCH64_INSN_FUNCS(b, 0xFC000000, 0x14000000) >> __AARCH64_INSN_FUNCS(bl, 0xFC000000, 0x94000000) >> +__AARCH64_INSN_FUNCS(b_bl, 0x7C000000, 0x14000000) > > Why do we need this when we already have checks for b and bl? I was trying to avoid doing multiple checks for different variants of similar instructions. > >> +__AARCH64_INSN_FUNCS(cb, 0x7E000000, 0x34000000) > > Likewise for cbz and cbnz... > >> __AARCH64_INSN_FUNCS(cbz, 0x7F000000, 0x34000000) >> __AARCH64_INSN_FUNCS(cbnz, 0x7F000000, 0x35000000) >> +__AARCH64_INSN_FUNCS(tb, 0x7E000000, 0x36000000) > > ... there's a pattern here! > ^^ >> __AARCH64_INSN_FUNCS(tbz, 0x7F000000, 0x36000000) >> __AARCH64_INSN_FUNCS(tbnz, 0x7F000000, 0x37000000) >> +__AARCH64_INSN_FUNCS(b_bl_cb_tb, 0x5C000000, 0x14000000) > > I must be missing something :) ^^ > >> __AARCH64_INSN_FUNCS(bcond, 0xFF000010, 0x54000000) >> __AARCH64_INSN_FUNCS(svc, 0xFFE0001F, 0xD4000001) >> __AARCH64_INSN_FUNCS(hvc, 0xFFE0001F, 0xD4000002) >> __AARCH64_INSN_FUNCS(smc, 0xFFE0001F, 0xD4000003) >> __AARCH64_INSN_FUNCS(brk, 0xFFE0001F, 0xD4200000) >> +__AARCH64_INSN_FUNCS(exception, 0xFF000000, 0xD4000000) >> __AARCH64_INSN_FUNCS(hint, 0xFFFFF01F, 0xD503201F) >> __AARCH64_INSN_FUNCS(br, 0xFFFFFC1F, 0xD61F0000) >> __AARCH64_INSN_FUNCS(blr, 0xFFFFFC1F, 0xD63F0000) >> +__AARCH64_INSN_FUNCS(br_blr, 0xFFDFFC1F, 0xD61F0000) >> __AARCH64_INSN_FUNCS(ret, 0xFFFFFC1F, 0xD65F0000) >> +__AARCH64_INSN_FUNCS(msr_imm, 0xFFF8F01F, 0xD500401F) >> +__AARCH64_INSN_FUNCS(msr_reg, 0xFFF00000, 0xD5100000) >> +__AARCH64_INSN_FUNCS(set_clr_daif, 0xFFFFF0DF, 0xD50340DF) >> +__AARCH64_INSN_FUNCS(rd_wr_daif, 0xFFDFFFE0, 0xD51B4220) > > I think I'd rather have separate decoders to decode the register field > of an mrs/msr instruction than overload each encoding here. > > Anyway, on the whole this looks pretty good, I'd just prefer not to build > compound instruction checks at the encoding level (even though it looks > like you did a good job on the values). > OK, easy enough to just add to the if statements where these are getting used. May be getting a little bloated looking there though. -dl -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
diff --git a/arch/arm64/include/asm/insn.h b/arch/arm64/include/asm/insn.h index 30e50eb..66bfb21 100644 --- a/arch/arm64/include/asm/insn.h +++ b/arch/arm64/include/asm/insn.h @@ -223,8 +223,13 @@ static __always_inline bool aarch64_insn_is_##abbr(u32 code) \ static __always_inline u32 aarch64_insn_get_##abbr##_value(void) \ { return (val); } +__AARCH64_INSN_FUNCS(adr_adrp, 0x1F000000, 0x10000000) +__AARCH64_INSN_FUNCS(prfm_lit, 0xFF000000, 0xD8000000) __AARCH64_INSN_FUNCS(str_reg, 0x3FE0EC00, 0x38206800) __AARCH64_INSN_FUNCS(ldr_reg, 0x3FE0EC00, 0x38606800) +__AARCH64_INSN_FUNCS(ldr_lit, 0xBF000000, 0x18000000) +__AARCH64_INSN_FUNCS(ldrsw_lit, 0xFF000000, 0x98000000) +__AARCH64_INSN_FUNCS(exclusive, 0x3F000000, 0x08000000) __AARCH64_INSN_FUNCS(stp_post, 0x7FC00000, 0x28800000) __AARCH64_INSN_FUNCS(ldp_post, 0x7FC00000, 0x28C00000) __AARCH64_INSN_FUNCS(stp_pre, 0x7FC00000, 0x29800000) @@ -264,19 +269,29 @@ __AARCH64_INSN_FUNCS(ands, 0x7F200000, 0x6A000000) __AARCH64_INSN_FUNCS(bics, 0x7F200000, 0x6A200000) __AARCH64_INSN_FUNCS(b, 0xFC000000, 0x14000000) __AARCH64_INSN_FUNCS(bl, 0xFC000000, 0x94000000) +__AARCH64_INSN_FUNCS(b_bl, 0x7C000000, 0x14000000) +__AARCH64_INSN_FUNCS(cb, 0x7E000000, 0x34000000) __AARCH64_INSN_FUNCS(cbz, 0x7F000000, 0x34000000) __AARCH64_INSN_FUNCS(cbnz, 0x7F000000, 0x35000000) +__AARCH64_INSN_FUNCS(tb, 0x7E000000, 0x36000000) __AARCH64_INSN_FUNCS(tbz, 0x7F000000, 0x36000000) __AARCH64_INSN_FUNCS(tbnz, 0x7F000000, 0x37000000) +__AARCH64_INSN_FUNCS(b_bl_cb_tb, 0x5C000000, 0x14000000) __AARCH64_INSN_FUNCS(bcond, 0xFF000010, 0x54000000) __AARCH64_INSN_FUNCS(svc, 0xFFE0001F, 0xD4000001) __AARCH64_INSN_FUNCS(hvc, 0xFFE0001F, 0xD4000002) __AARCH64_INSN_FUNCS(smc, 0xFFE0001F, 0xD4000003) __AARCH64_INSN_FUNCS(brk, 0xFFE0001F, 0xD4200000) +__AARCH64_INSN_FUNCS(exception, 0xFF000000, 0xD4000000) __AARCH64_INSN_FUNCS(hint, 0xFFFFF01F, 0xD503201F) __AARCH64_INSN_FUNCS(br, 0xFFFFFC1F, 0xD61F0000) __AARCH64_INSN_FUNCS(blr, 0xFFFFFC1F, 0xD63F0000) +__AARCH64_INSN_FUNCS(br_blr, 0xFFDFFC1F, 0xD61F0000) __AARCH64_INSN_FUNCS(ret, 0xFFFFFC1F, 0xD65F0000) +__AARCH64_INSN_FUNCS(msr_imm, 0xFFF8F01F, 0xD500401F) +__AARCH64_INSN_FUNCS(msr_reg, 0xFFF00000, 0xD5100000) +__AARCH64_INSN_FUNCS(set_clr_daif, 0xFFFFF0DF, 0xD50340DF) +__AARCH64_INSN_FUNCS(rd_wr_daif, 0xFFDFFFE0, 0xD51B4220) #undef __AARCH64_INSN_FUNCS @@ -286,6 +301,9 @@ bool aarch64_insn_is_branch_imm(u32 insn); int aarch64_insn_read(void *addr, u32 *insnp); int aarch64_insn_write(void *addr, u32 insn); enum aarch64_insn_encoding_class aarch64_get_insn_class(u32 insn); +bool aarch64_insn_uses_literal(u32 insn); +bool aarch64_insn_is_branch(u32 insn); +bool aarch64_insn_is_daif_access(u32 insn); u64 aarch64_insn_decode_immediate(enum aarch64_insn_imm_type type, u32 insn); u32 aarch64_insn_encode_immediate(enum aarch64_insn_imm_type type, u32 insn, u64 imm); diff --git a/arch/arm64/kernel/insn.c b/arch/arm64/kernel/insn.c index dd9671c..e532188 100644 --- a/arch/arm64/kernel/insn.c +++ b/arch/arm64/kernel/insn.c @@ -163,6 +163,34 @@ static bool __kprobes __aarch64_insn_hotpatch_safe(u32 insn) aarch64_insn_is_nop(insn); } +bool __kprobes aarch64_insn_uses_literal(u32 insn) +{ + /* ldr/ldrsw (literal), prfm */ + + return aarch64_insn_is_ldr_lit(insn) || + aarch64_insn_is_ldrsw_lit(insn) || + aarch64_insn_is_adr_adrp(insn) || + aarch64_insn_is_prfm_lit(insn); +} + +bool __kprobes aarch64_insn_is_branch(u32 insn) +{ + /* b, bl, cb*, tb*, b.cond, br, blr */ + + return aarch64_insn_is_b_bl_cb_tb(insn) || + aarch64_insn_is_br_blr(insn) || + aarch64_insn_is_ret(insn) || + aarch64_insn_is_bcond(insn); +} + +bool __kprobes aarch64_insn_is_daif_access(u32 insn) +{ + /* msr daif, mrs daif, msr daifset, msr daifclr */ + + return aarch64_insn_is_rd_wr_daif(insn) || + aarch64_insn_is_set_clr_daif(insn); +} + /* * ARM Architecture Reference Manual for ARMv8 Profile-A, Issue A.a * Section B2.6.5 "Concurrent modification and execution of instructions":