From 3b143cca6e1397188f507a6c727f4108861ceb8b Mon Sep 17 00:00:00 2001 From: "Maciej W. Rozycki" Date: Fri, 4 Mar 2016 01:44:28 +0000 Subject: [PATCH] MIPS: traps: Correct the SIGTRAP debug ABI in `do_watch' and `do_trap_or_bp' Follow our own rules set in for SIGTRAP signals issued from `do_watch' and `do_trap_or_bp' by setting the signal code to TRAP_HWBKPT and TRAP_BRKPT respectively, for Watch exceptions and for those Breakpoint exceptions whose originating BREAK instruction's code does not have a special meaning. Keep Trap exceptions unaffected as these are not debug events. No existing user software is expected to examine signal codes for these signals as SI_KERNEL has been always used here. This change makes the MIPS port more like other Linux ports, which reduces the complexity and provides for performance improvement in GDB. Signed-off-by: Maciej W. Rozycki Cc: Pedro Alves Cc: Luis Machado Cc: linux-mips@linux-mips.org Cc: gdb@sourceware.org Patchwork: https://patchwork.linux-mips.org/patch/12758/ Signed-off-by: Ralf Baechle --- arch/mips/include/asm/mips-r2-to-r6-emul.h | 2 +- arch/mips/kernel/mips-r2-to-r6-emul.c | 12 ++++++------ arch/mips/kernel/traps.c | 18 +++++++++++++----- 3 files changed, 20 insertions(+), 12 deletions(-) diff --git a/arch/mips/include/asm/mips-r2-to-r6-emul.h b/arch/mips/include/asm/mips-r2-to-r6-emul.h index 1f6ea8352ca9..20621e1ca238 100644 --- a/arch/mips/include/asm/mips-r2-to-r6-emul.h +++ b/arch/mips/include/asm/mips-r2-to-r6-emul.h @@ -79,7 +79,7 @@ struct r2_decoder_table { }; -extern void do_trap_or_bp(struct pt_regs *regs, unsigned int code, +extern void do_trap_or_bp(struct pt_regs *regs, unsigned int code, int si_code, const char *str); #ifndef CONFIG_MIPSR2_TO_R6_EMULATOR diff --git a/arch/mips/kernel/mips-r2-to-r6-emul.c b/arch/mips/kernel/mips-r2-to-r6-emul.c index 1f5aac7f9ec3..3fff89ae760b 100644 --- a/arch/mips/kernel/mips-r2-to-r6-emul.c +++ b/arch/mips/kernel/mips-r2-to-r6-emul.c @@ -940,42 +940,42 @@ repeat: switch (rt) { case tgei_op: if ((long)regs->regs[rs] >= MIPSInst_SIMM(inst)) - do_trap_or_bp(regs, 0, "TGEI"); + do_trap_or_bp(regs, 0, 0, "TGEI"); MIPS_R2_STATS(traps); break; case tgeiu_op: if (regs->regs[rs] >= MIPSInst_UIMM(inst)) - do_trap_or_bp(regs, 0, "TGEIU"); + do_trap_or_bp(regs, 0, 0, "TGEIU"); MIPS_R2_STATS(traps); break; case tlti_op: if ((long)regs->regs[rs] < MIPSInst_SIMM(inst)) - do_trap_or_bp(regs, 0, "TLTI"); + do_trap_or_bp(regs, 0, 0, "TLTI"); MIPS_R2_STATS(traps); break; case tltiu_op: if (regs->regs[rs] < MIPSInst_UIMM(inst)) - do_trap_or_bp(regs, 0, "TLTIU"); + do_trap_or_bp(regs, 0, 0, "TLTIU"); MIPS_R2_STATS(traps); break; case teqi_op: if (regs->regs[rs] == MIPSInst_SIMM(inst)) - do_trap_or_bp(regs, 0, "TEQI"); + do_trap_or_bp(regs, 0, 0, "TEQI"); MIPS_R2_STATS(traps); break; case tnei_op: if (regs->regs[rs] != MIPSInst_SIMM(inst)) - do_trap_or_bp(regs, 0, "TNEI"); + do_trap_or_bp(regs, 0, 0, "TNEI"); MIPS_R2_STATS(traps); diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c index e701eb0aa99c..80339ce64521 100644 --- a/arch/mips/kernel/traps.c +++ b/arch/mips/kernel/traps.c @@ -56,6 +56,7 @@ #include #include #include +#include #include #include #include @@ -871,7 +872,7 @@ out: exception_exit(prev_state); } -void do_trap_or_bp(struct pt_regs *regs, unsigned int code, +void do_trap_or_bp(struct pt_regs *regs, unsigned int code, int si_code, const char *str) { siginfo_t info = { 0 }; @@ -928,7 +929,13 @@ void do_trap_or_bp(struct pt_regs *regs, unsigned int code, default: scnprintf(b, sizeof(b), "%s instruction in kernel code", str); die_if_kernel(b, regs); - force_sig(SIGTRAP, current); + if (si_code) { + info.si_signo = SIGTRAP; + info.si_code = si_code; + force_sig_info(SIGTRAP, &info, current); + } else { + force_sig(SIGTRAP, current); + } } } @@ -1012,7 +1019,7 @@ asmlinkage void do_bp(struct pt_regs *regs) break; } - do_trap_or_bp(regs, bcode, "Break"); + do_trap_or_bp(regs, bcode, TRAP_BRKPT, "Break"); out: set_fs(seg); @@ -1054,7 +1061,7 @@ asmlinkage void do_tr(struct pt_regs *regs) tcode = (opcode >> 6) & ((1 << 10) - 1); } - do_trap_or_bp(regs, tcode, "Trap"); + do_trap_or_bp(regs, tcode, 0, "Trap"); out: set_fs(seg); @@ -1492,6 +1499,7 @@ asmlinkage void do_mdmx(struct pt_regs *regs) */ asmlinkage void do_watch(struct pt_regs *regs) { + siginfo_t info = { .si_signo = SIGTRAP, .si_code = TRAP_HWBKPT }; enum ctx_state prev_state; u32 cause; @@ -1512,7 +1520,7 @@ asmlinkage void do_watch(struct pt_regs *regs) if (test_tsk_thread_flag(current, TIF_LOAD_WATCH)) { mips_read_watch_registers(); local_irq_enable(); - force_sig(SIGTRAP, current); + force_sig_info(SIGTRAP, &info, current); } else { mips_clear_watch_registers(); local_irq_enable();