Re: [PATCH 4/6] signal/sparc: si_trapno is only used with SIGILL ILL_ILLTRP

From: Marco Elver
Date: Fri Jul 16 2021 - 07:49:26 EST


On Thu, 15 Jul 2021 at 20:12, Eric W. Biederman <ebiederm@xxxxxxxxxxxx> wrote:
> While reviewing the signal handlers on sparc it became clear that
> si_trapno is only set to a non-zero value when sending SIGILL with
> si_code ILL_ILLTRP.
>
> Add force_sig_fault_trapno and send SIGILL ILL_ILLTRP with it.
>
> Remove the define of __ARCH_SI_TRAPNO and remove the always zero
> si_trapno parameter from send_sig_fault and force_sig_fault.
>
> v1: https://lkml.kernel.org/r/m1eeers7q7.fsf_-_@xxxxxxxxxxxxxxxxx
> v2: https://lkml.kernel.org/r/20210505141101.11519-7-ebiederm@xxxxxxxxxxxx
> Signed-off-by: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>

Reviewed-by: Marco Elver <elver@xxxxxxxxxx>

> ---
> arch/sparc/include/uapi/asm/siginfo.h | 3 --
> arch/sparc/kernel/process_64.c | 2 +-
> arch/sparc/kernel/sys_sparc_32.c | 2 +-
> arch/sparc/kernel/sys_sparc_64.c | 2 +-
> arch/sparc/kernel/traps_32.c | 22 +++++++-------
> arch/sparc/kernel/traps_64.c | 44 ++++++++++++---------------
> arch/sparc/kernel/unaligned_32.c | 2 +-
> arch/sparc/mm/fault_32.c | 2 +-
> arch/sparc/mm/fault_64.c | 2 +-
> include/linux/sched/signal.h | 1 +
> kernel/signal.c | 19 ++++++++++++
> 11 files changed, 56 insertions(+), 45 deletions(-)
>
> diff --git a/arch/sparc/include/uapi/asm/siginfo.h b/arch/sparc/include/uapi/asm/siginfo.h
> index 68bdde4c2a2e..0e7c27522aed 100644
> --- a/arch/sparc/include/uapi/asm/siginfo.h
> +++ b/arch/sparc/include/uapi/asm/siginfo.h
> @@ -8,9 +8,6 @@
>
> #endif /* defined(__sparc__) && defined(__arch64__) */
>
> -
> -#define __ARCH_SI_TRAPNO
> -
> #include <asm-generic/siginfo.h>
>
>
> diff --git a/arch/sparc/kernel/process_64.c b/arch/sparc/kernel/process_64.c
> index d33c58a58d4f..547b06b49ce3 100644
> --- a/arch/sparc/kernel/process_64.c
> +++ b/arch/sparc/kernel/process_64.c
> @@ -518,7 +518,7 @@ void synchronize_user_stack(void)
>
> static void stack_unaligned(unsigned long sp)
> {
> - force_sig_fault(SIGBUS, BUS_ADRALN, (void __user *) sp, 0);
> + force_sig_fault(SIGBUS, BUS_ADRALN, (void __user *) sp);
> }
>
> static const char uwfault32[] = KERN_INFO \
> diff --git a/arch/sparc/kernel/sys_sparc_32.c b/arch/sparc/kernel/sys_sparc_32.c
> index be77538bc038..082a551897ed 100644
> --- a/arch/sparc/kernel/sys_sparc_32.c
> +++ b/arch/sparc/kernel/sys_sparc_32.c
> @@ -151,7 +151,7 @@ sparc_breakpoint (struct pt_regs *regs)
> #ifdef DEBUG_SPARC_BREAKPOINT
> printk ("TRAP: Entering kernel PC=%x, nPC=%x\n", regs->pc, regs->npc);
> #endif
> - force_sig_fault(SIGTRAP, TRAP_BRKPT, (void __user *)regs->pc, 0);
> + force_sig_fault(SIGTRAP, TRAP_BRKPT, (void __user *)regs->pc);
>
> #ifdef DEBUG_SPARC_BREAKPOINT
> printk ("TRAP: Returning to space: PC=%x nPC=%x\n", regs->pc, regs->npc);
> diff --git a/arch/sparc/kernel/sys_sparc_64.c b/arch/sparc/kernel/sys_sparc_64.c
> index 6b92fadb6ec7..1e9a9e016237 100644
> --- a/arch/sparc/kernel/sys_sparc_64.c
> +++ b/arch/sparc/kernel/sys_sparc_64.c
> @@ -514,7 +514,7 @@ asmlinkage void sparc_breakpoint(struct pt_regs *regs)
> #ifdef DEBUG_SPARC_BREAKPOINT
> printk ("TRAP: Entering kernel PC=%lx, nPC=%lx\n", regs->tpc, regs->tnpc);
> #endif
> - force_sig_fault(SIGTRAP, TRAP_BRKPT, (void __user *)regs->tpc, 0);
> + force_sig_fault(SIGTRAP, TRAP_BRKPT, (void __user *)regs->tpc);
> #ifdef DEBUG_SPARC_BREAKPOINT
> printk ("TRAP: Returning to space: PC=%lx nPC=%lx\n", regs->tpc, regs->tnpc);
> #endif
> diff --git a/arch/sparc/kernel/traps_32.c b/arch/sparc/kernel/traps_32.c
> index 247a0d9683b2..5630e5a395e0 100644
> --- a/arch/sparc/kernel/traps_32.c
> +++ b/arch/sparc/kernel/traps_32.c
> @@ -102,8 +102,8 @@ void do_hw_interrupt(struct pt_regs *regs, unsigned long type)
> if(regs->psr & PSR_PS)
> die_if_kernel("Kernel bad trap", regs);
>
> - force_sig_fault(SIGILL, ILL_ILLTRP,
> - (void __user *)regs->pc, type - 0x80);
> + force_sig_fault_trapno(SIGILL, ILL_ILLTRP,
> + (void __user *)regs->pc, type - 0x80);
> }
>
> void do_illegal_instruction(struct pt_regs *regs, unsigned long pc, unsigned long npc,
> @@ -116,7 +116,7 @@ void do_illegal_instruction(struct pt_regs *regs, unsigned long pc, unsigned lon
> regs->pc, *(unsigned long *)regs->pc);
> #endif
>
> - send_sig_fault(SIGILL, ILL_ILLOPC, (void __user *)pc, 0, current);
> + send_sig_fault(SIGILL, ILL_ILLOPC, (void __user *)pc, current);
> }
>
> void do_priv_instruction(struct pt_regs *regs, unsigned long pc, unsigned long npc,
> @@ -124,7 +124,7 @@ void do_priv_instruction(struct pt_regs *regs, unsigned long pc, unsigned long n
> {
> if(psr & PSR_PS)
> die_if_kernel("Penguin instruction from Penguin mode??!?!", regs);
> - send_sig_fault(SIGILL, ILL_PRVOPC, (void __user *)pc, 0, current);
> + send_sig_fault(SIGILL, ILL_PRVOPC, (void __user *)pc, current);
> }
>
> /* XXX User may want to be allowed to do this. XXX */
> @@ -145,7 +145,7 @@ void do_memaccess_unaligned(struct pt_regs *regs, unsigned long pc, unsigned lon
> #endif
> send_sig_fault(SIGBUS, BUS_ADRALN,
> /* FIXME: Should dig out mna address */ (void *)0,
> - 0, current);
> + current);
> }
>
> static unsigned long init_fsr = 0x0UL;
> @@ -291,7 +291,7 @@ void do_fpe_trap(struct pt_regs *regs, unsigned long pc, unsigned long npc,
> else if (fsr & 0x01)
> code = FPE_FLTRES;
> }
> - send_sig_fault(SIGFPE, code, (void __user *)pc, 0, fpt);
> + send_sig_fault(SIGFPE, code, (void __user *)pc, fpt);
> #ifndef CONFIG_SMP
> last_task_used_math = NULL;
> #endif
> @@ -305,7 +305,7 @@ void handle_tag_overflow(struct pt_regs *regs, unsigned long pc, unsigned long n
> {
> if(psr & PSR_PS)
> die_if_kernel("Penguin overflow trap from kernel mode", regs);
> - send_sig_fault(SIGEMT, EMT_TAGOVF, (void __user *)pc, 0, current);
> + send_sig_fault(SIGEMT, EMT_TAGOVF, (void __user *)pc, current);
> }
>
> void handle_watchpoint(struct pt_regs *regs, unsigned long pc, unsigned long npc,
> @@ -327,13 +327,13 @@ void handle_reg_access(struct pt_regs *regs, unsigned long pc, unsigned long npc
> printk("Register Access Exception at PC %08lx NPC %08lx PSR %08lx\n",
> pc, npc, psr);
> #endif
> - force_sig_fault(SIGBUS, BUS_OBJERR, (void __user *)pc, 0);
> + force_sig_fault(SIGBUS, BUS_OBJERR, (void __user *)pc);
> }
>
> void handle_cp_disabled(struct pt_regs *regs, unsigned long pc, unsigned long npc,
> unsigned long psr)
> {
> - send_sig_fault(SIGILL, ILL_COPROC, (void __user *)pc, 0, current);
> + send_sig_fault(SIGILL, ILL_COPROC, (void __user *)pc, current);
> }
>
> void handle_cp_exception(struct pt_regs *regs, unsigned long pc, unsigned long npc,
> @@ -343,13 +343,13 @@ void handle_cp_exception(struct pt_regs *regs, unsigned long pc, unsigned long n
> printk("Co-Processor Exception at PC %08lx NPC %08lx PSR %08lx\n",
> pc, npc, psr);
> #endif
> - send_sig_fault(SIGILL, ILL_COPROC, (void __user *)pc, 0, current);
> + send_sig_fault(SIGILL, ILL_COPROC, (void __user *)pc, current);
> }
>
> void handle_hw_divzero(struct pt_regs *regs, unsigned long pc, unsigned long npc,
> unsigned long psr)
> {
> - send_sig_fault(SIGFPE, FPE_INTDIV, (void __user *)pc, 0, current);
> + send_sig_fault(SIGFPE, FPE_INTDIV, (void __user *)pc, current);
> }
>
> #ifdef CONFIG_DEBUG_BUGVERBOSE
> diff --git a/arch/sparc/kernel/traps_64.c b/arch/sparc/kernel/traps_64.c
> index a850dccd78ea..6863025ed56d 100644
> --- a/arch/sparc/kernel/traps_64.c
> +++ b/arch/sparc/kernel/traps_64.c
> @@ -107,8 +107,8 @@ void bad_trap(struct pt_regs *regs, long lvl)
> regs->tpc &= 0xffffffff;
> regs->tnpc &= 0xffffffff;
> }
> - force_sig_fault(SIGILL, ILL_ILLTRP,
> - (void __user *)regs->tpc, lvl);
> + force_sig_fault_trapno(SIGILL, ILL_ILLTRP,
> + (void __user *)regs->tpc, lvl);
> }
>
> void bad_trap_tl1(struct pt_regs *regs, long lvl)
> @@ -201,8 +201,7 @@ void spitfire_insn_access_exception(struct pt_regs *regs, unsigned long sfsr, un
> regs->tpc &= 0xffffffff;
> regs->tnpc &= 0xffffffff;
> }
> - force_sig_fault(SIGSEGV, SEGV_MAPERR,
> - (void __user *)regs->tpc, 0);
> + force_sig_fault(SIGSEGV, SEGV_MAPERR, (void __user *)regs->tpc);
> out:
> exception_exit(prev_state);
> }
> @@ -237,7 +236,7 @@ void sun4v_insn_access_exception(struct pt_regs *regs, unsigned long addr, unsig
> regs->tpc &= 0xffffffff;
> regs->tnpc &= 0xffffffff;
> }
> - force_sig_fault(SIGSEGV, SEGV_MAPERR, (void __user *) addr, 0);
> + force_sig_fault(SIGSEGV, SEGV_MAPERR, (void __user *) addr);
> }
>
> void sun4v_insn_access_exception_tl1(struct pt_regs *regs, unsigned long addr, unsigned long type_ctx)
> @@ -321,7 +320,7 @@ void spitfire_data_access_exception(struct pt_regs *regs, unsigned long sfsr, un
> if (is_no_fault_exception(regs))
> return;
>
> - force_sig_fault(SIGSEGV, SEGV_MAPERR, (void __user *)sfar, 0);
> + force_sig_fault(SIGSEGV, SEGV_MAPERR, (void __user *)sfar);
> out:
> exception_exit(prev_state);
> }
> @@ -385,13 +384,13 @@ void sun4v_data_access_exception(struct pt_regs *regs, unsigned long addr, unsig
> */
> switch (type) {
> case HV_FAULT_TYPE_INV_ASI:
> - force_sig_fault(SIGILL, ILL_ILLADR, (void __user *)addr, 0);
> + force_sig_fault(SIGILL, ILL_ILLADR, (void __user *)addr);
> break;
> case HV_FAULT_TYPE_MCD_DIS:
> - force_sig_fault(SIGSEGV, SEGV_ACCADI, (void __user *)addr, 0);
> + force_sig_fault(SIGSEGV, SEGV_ACCADI, (void __user *)addr);
> break;
> default:
> - force_sig_fault(SIGSEGV, SEGV_MAPERR, (void __user *)addr, 0);
> + force_sig_fault(SIGSEGV, SEGV_MAPERR, (void __user *)addr);
> break;
> }
> }
> @@ -568,7 +567,7 @@ static void spitfire_ue_log(unsigned long afsr, unsigned long afar, unsigned lon
> regs->tpc &= 0xffffffff;
> regs->tnpc &= 0xffffffff;
> }
> - force_sig_fault(SIGBUS, BUS_OBJERR, (void *)0, 0);
> + force_sig_fault(SIGBUS, BUS_OBJERR, (void *)0);
> }
>
> void spitfire_access_error(struct pt_regs *regs, unsigned long status_encoded, unsigned long afar)
> @@ -2069,8 +2068,7 @@ void do_mcd_err(struct pt_regs *regs, struct sun4v_error_entry ent)
> /* Send SIGSEGV to the userspace process with the right signal
> * code
> */
> - force_sig_fault(SIGSEGV, SEGV_ADIDERR, (void __user *)ent.err_raddr,
> - 0);
> + force_sig_fault(SIGSEGV, SEGV_ADIDERR, (void __user *)ent.err_raddr);
> }
>
> /* We run with %pil set to PIL_NORMAL_MAX and PSTATE_IE enabled in %pstate.
> @@ -2184,7 +2182,7 @@ bool sun4v_nonresum_error_user_handled(struct pt_regs *regs,
> }
> if (attrs & SUN4V_ERR_ATTRS_PIO) {
> force_sig_fault(SIGBUS, BUS_ADRERR,
> - (void __user *)sun4v_get_vaddr(regs), 0);
> + (void __user *)sun4v_get_vaddr(regs));
> return true;
> }
>
> @@ -2340,8 +2338,7 @@ static void do_fpe_common(struct pt_regs *regs)
> else if (fsr & 0x01)
> code = FPE_FLTRES;
> }
> - force_sig_fault(SIGFPE, code,
> - (void __user *)regs->tpc, 0);
> + force_sig_fault(SIGFPE, code, (void __user *)regs->tpc);
> }
> }
>
> @@ -2395,8 +2392,7 @@ void do_tof(struct pt_regs *regs)
> regs->tpc &= 0xffffffff;
> regs->tnpc &= 0xffffffff;
> }
> - force_sig_fault(SIGEMT, EMT_TAGOVF,
> - (void __user *)regs->tpc, 0);
> + force_sig_fault(SIGEMT, EMT_TAGOVF, (void __user *)regs->tpc);
> out:
> exception_exit(prev_state);
> }
> @@ -2415,8 +2411,7 @@ void do_div0(struct pt_regs *regs)
> regs->tpc &= 0xffffffff;
> regs->tnpc &= 0xffffffff;
> }
> - force_sig_fault(SIGFPE, FPE_INTDIV,
> - (void __user *)regs->tpc, 0);
> + force_sig_fault(SIGFPE, FPE_INTDIV, (void __user *)regs->tpc);
> out:
> exception_exit(prev_state);
> }
> @@ -2612,7 +2607,7 @@ void do_illegal_instruction(struct pt_regs *regs)
> }
> }
> }
> - force_sig_fault(SIGILL, ILL_ILLOPC, (void __user *)pc, 0);
> + force_sig_fault(SIGILL, ILL_ILLOPC, (void __user *)pc);
> out:
> exception_exit(prev_state);
> }
> @@ -2632,7 +2627,7 @@ void mem_address_unaligned(struct pt_regs *regs, unsigned long sfar, unsigned lo
> if (is_no_fault_exception(regs))
> return;
>
> - force_sig_fault(SIGBUS, BUS_ADRALN, (void __user *)sfar, 0);
> + force_sig_fault(SIGBUS, BUS_ADRALN, (void __user *)sfar);
> out:
> exception_exit(prev_state);
> }
> @@ -2650,7 +2645,7 @@ void sun4v_do_mna(struct pt_regs *regs, unsigned long addr, unsigned long type_c
> if (is_no_fault_exception(regs))
> return;
>
> - force_sig_fault(SIGBUS, BUS_ADRALN, (void __user *) addr, 0);
> + force_sig_fault(SIGBUS, BUS_ADRALN, (void __user *) addr);
> }
>
> /* sun4v_mem_corrupt_detect_precise() - Handle precise exception on an ADI
> @@ -2697,7 +2692,7 @@ void sun4v_mem_corrupt_detect_precise(struct pt_regs *regs, unsigned long addr,
> regs->tpc &= 0xffffffff;
> regs->tnpc &= 0xffffffff;
> }
> - force_sig_fault(SIGSEGV, SEGV_ADIPERR, (void __user *)addr, 0);
> + force_sig_fault(SIGSEGV, SEGV_ADIPERR, (void __user *)addr);
> }
>
> void do_privop(struct pt_regs *regs)
> @@ -2712,8 +2707,7 @@ void do_privop(struct pt_regs *regs)
> regs->tpc &= 0xffffffff;
> regs->tnpc &= 0xffffffff;
> }
> - force_sig_fault(SIGILL, ILL_PRVOPC,
> - (void __user *)regs->tpc, 0);
> + force_sig_fault(SIGILL, ILL_PRVOPC, (void __user *)regs->tpc);
> out:
> exception_exit(prev_state);
> }
> diff --git a/arch/sparc/kernel/unaligned_32.c b/arch/sparc/kernel/unaligned_32.c
> index ef5c5207c9ff..455f0258c745 100644
> --- a/arch/sparc/kernel/unaligned_32.c
> +++ b/arch/sparc/kernel/unaligned_32.c
> @@ -278,5 +278,5 @@ asmlinkage void user_unaligned_trap(struct pt_regs *regs, unsigned int insn)
> {
> send_sig_fault(SIGBUS, BUS_ADRALN,
> (void __user *)safe_compute_effective_address(regs, insn),
> - 0, current);
> + current);
> }
> diff --git a/arch/sparc/mm/fault_32.c b/arch/sparc/mm/fault_32.c
> index de2031c2b2d7..fa858626b85b 100644
> --- a/arch/sparc/mm/fault_32.c
> +++ b/arch/sparc/mm/fault_32.c
> @@ -83,7 +83,7 @@ static void __do_fault_siginfo(int code, int sig, struct pt_regs *regs,
> show_signal_msg(regs, sig, code,
> addr, current);
>
> - force_sig_fault(sig, code, (void __user *) addr, 0);
> + force_sig_fault(sig, code, (void __user *) addr);
> }
>
> static unsigned long compute_si_addr(struct pt_regs *regs, int text_fault)
> diff --git a/arch/sparc/mm/fault_64.c b/arch/sparc/mm/fault_64.c
> index 0a6bcc85fba7..9a9652a15fed 100644
> --- a/arch/sparc/mm/fault_64.c
> +++ b/arch/sparc/mm/fault_64.c
> @@ -176,7 +176,7 @@ static void do_fault_siginfo(int code, int sig, struct pt_regs *regs,
> if (unlikely(show_unhandled_signals))
> show_signal_msg(regs, sig, code, addr, current);
>
> - force_sig_fault(sig, code, (void __user *) addr, 0);
> + force_sig_fault(sig, code, (void __user *) addr);
> }
>
> static unsigned int get_fault_insn(struct pt_regs *regs, unsigned int insn)
> diff --git a/include/linux/sched/signal.h b/include/linux/sched/signal.h
> index b9126fe06c3f..99a9ab2b169a 100644
> --- a/include/linux/sched/signal.h
> +++ b/include/linux/sched/signal.h
> @@ -329,6 +329,7 @@ int force_sig_pkuerr(void __user *addr, u32 pkey);
> int force_sig_perf(void __user *addr, u32 type, u64 sig_data);
>
> int force_sig_ptrace_errno_trap(int errno, void __user *addr);
> +int force_sig_fault_trapno(int sig, int code, void __user *addr, int trapno);
>
> extern int send_sig_info(int, struct kernel_siginfo *, struct task_struct *);
> extern void force_sigsegv(int sig);
> diff --git a/kernel/signal.c b/kernel/signal.c
> index a3229add4455..87a374225277 100644
> --- a/kernel/signal.c
> +++ b/kernel/signal.c
> @@ -1808,6 +1808,22 @@ int force_sig_ptrace_errno_trap(int errno, void __user *addr)
> return force_sig_info(&info);
> }
>
> +/* For the rare architectures that include trap information using
> + * si_trapno.
> + */
> +int force_sig_fault_trapno(int sig, int code, void __user *addr, int trapno)
> +{
> + struct kernel_siginfo info;
> +
> + clear_siginfo(&info);
> + info.si_signo = sig;
> + info.si_errno = 0;
> + info.si_code = code;
> + info.si_addr = addr;
> + info.si_trapno = trapno;
> + return force_sig_info(&info);
> +}
> +
> int kill_pgrp(struct pid *pid, int sig, int priv)
> {
> int ret;
> @@ -3243,6 +3259,9 @@ enum siginfo_layout siginfo_layout(unsigned sig, int si_code)
> #endif
> else if ((sig == SIGTRAP) && (si_code == TRAP_PERF))
> layout = SIL_PERF_EVENT;
> + else if (IS_ENABLED(CONFIG_SPARC) &&
> + (sig == SIGILL) && (si_code == ILL_ILLTRP))
> + layout = SIL_FAULT_TRAPNO;
> #ifdef __ARCH_SI_TRAPNO
> else if (layout == SIL_FAULT)
> layout = SIL_FAULT_TRAPNO;
> --
> 2.20.1
>
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