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charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org On Tue, Dec 06, 2022 at 12:42:16AM +0800, Jisheng Zhang wrote: > On Mon, Dec 05, 2022 at 03:57:10PM +0100, Andrew Jones wrote: > > On Mon, Dec 05, 2022 at 01:46:20AM +0800, Jisheng Zhang wrote: > > > Alternatives live in a different section, so offsets used by jal > > > instruction will point to wrong locations after the patch got applied. > > > > > > Similar to arm64, adjust the location to consider that offset. > > > > > > Signed-off-by: Jisheng Zhang > > > --- > > > arch/riscv/include/asm/alternative.h | 2 ++ > > > arch/riscv/kernel/alternative.c | 38 ++++++++++++++++++++++++++++ > > > arch/riscv/kernel/cpufeature.c | 3 +++ > > > 3 files changed, 43 insertions(+) > > > > > > diff --git a/arch/riscv/include/asm/alternative.h b/arch/riscv/include/asm/alternative.h > > > index c58ec3cc4bc3..33eae9541684 100644 > > > --- a/arch/riscv/include/asm/alternative.h > > > +++ b/arch/riscv/include/asm/alternative.h > > > @@ -29,6 +29,8 @@ void apply_module_alternatives(void *start, size_t length); > > > > > > void riscv_alternative_fix_auipc_jalr(void *alt_ptr, unsigned int len, > > > int patch_offset); > > > +void riscv_alternative_fix_jal(void *alt_ptr, unsigned int len, > > > + int patch_offset); > > > > > > struct alt_entry { > > > void *old_ptr; /* address of original instruciton or data */ > > > diff --git a/arch/riscv/kernel/alternative.c b/arch/riscv/kernel/alternative.c > > > index 292cc42dc3be..9d88375624b5 100644 > > > --- a/arch/riscv/kernel/alternative.c > > > +++ b/arch/riscv/kernel/alternative.c > > > @@ -125,6 +125,44 @@ void riscv_alternative_fix_auipc_jalr(void *alt_ptr, unsigned int len, > > > } > > > } > > > > > > +#define to_jal_imm(value) \ > > > + (((value & (RV_J_IMM_10_1_MASK << RV_J_IMM_10_1_OFF)) << RV_I_IMM_11_0_OPOFF) | \ > > ^ RV_J_IMM_10_1_OPOFF > > > > > + ((value & (RV_J_IMM_11_MASK << RV_J_IMM_11_OFF)) << RV_J_IMM_11_OPOFF) | \ > > > + ((value & (RV_J_IMM_19_12_OPOFF << RV_J_IMM_19_12_OFF)) << RV_J_IMM_19_12_OPOFF) | \ > > > + ((value & (1 << RV_J_IMM_SIGN_OFF)) << RV_J_IMM_SIGN_OPOFF)) > > Hi all, > > I believe there's bug in the to_jal_imm() macro implementation, the > correct one should be like this: > > #define to_jal_imm(value) \ > ((RV_X(value, RV_J_IMM_10_1_OFF, RV_J_IMM_10_1_MASK) << RV_J_IMM_10_1_OPOFF) | \ > (RV_X(value, RV_J_IMM_11_OFF, RV_J_IMM_11_MASK) << RV_J_IMM_11_OPOFF) | \ > (RV_X(value, RV_J_IMM_19_12_OFF, RV_J_IMM_19_12_MASK) << RV_J_IMM_19_12_OPOFF) | \ > (RV_X(value, RV_J_IMM_SIGN_OFF, 1) << RV_J_IMM_SIGN_OPOFF)) And I just tested to_jal_imm() vs RV_EXTRACT_JTYPE_IMM(), they match perfectly. E.g: RV_EXTRACT_JTYPE_IMM(to_jal_imm(imm)) == imm is alway true when imm is a jal valid offset. > > Will fix it in next version. > > Thanks > > > > Should put () around value > > > > > + > > > +void riscv_alternative_fix_jal(void *alt_ptr, unsigned int len, > > > + int patch_offset) > > > +{ > > > + int num_instr = len / sizeof(u32); > > > + unsigned int call; > > > + int i; > > > + int imm; > > > + > > > + for (i = 0; i < num_instr; i++) { > > > + u32 inst = riscv_instruction_at(alt_ptr, i); > > > + > > > + if (!riscv_insn_is_jal(inst)) > > > + continue; > > > + > > > + /* get and adjust new target address */ > > > + imm = RV_EXTRACT_JTYPE_IMM(inst); > > > + imm -= patch_offset; > > > + > > > + /* pick the original jal */ > > > + call = inst; > > > + > > > + /* drop the old IMMs, all jal imm bits sit at 31:12 */ > > > + call &= ~GENMASK(31, 12); > > > > It'd be nice if this had a define. > > > > > + > > > + /* add the adapted IMMs */ > > > + call |= to_jal_imm(imm); > > > + > > > + /* patch the call place again */ > > > + patch_text_nosync(alt_ptr + i * sizeof(u32), &call, 4); > > > + } > > > +} > > > + > > > /* > > > * This is called very early in the boot process (directly after we run > > > * a feature detect on the boot CPU). No need to worry about other CPUs > > > diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c > > > index ba62a4ff5ccd..c743f0adc794 100644 > > > --- a/arch/riscv/kernel/cpufeature.c > > > +++ b/arch/riscv/kernel/cpufeature.c > > > @@ -324,6 +324,9 @@ void __init_or_module riscv_cpufeature_patch_func(struct alt_entry *begin, > > > riscv_alternative_fix_auipc_jalr(alt->old_ptr, > > > alt->alt_len, > > > alt->old_ptr - alt->alt_ptr); > > > + riscv_alternative_fix_jal(alt->old_ptr, > > > + alt->alt_len, > > > + alt->old_ptr - alt->alt_ptr); > > > } > > > } > > > } > > > -- > > > 2.37.2 > > > > > > > Thanks, > > drew _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv