Re: [PATCH 2/3] signal: Implement SIL_FAULT_TRAPNO

From: Eric W. Biederman
Date: Sun May 02 2021 - 14:25:22 EST

Next message: Eric W. Biederman: "Re: [PATCH 1/3] siginfo: Move si_trapno inside the union inside _si_fault"
Previous message: Linus Torvalds: "Re: [git pull] work.misc"
In reply to: Marco Elver: "Re: [PATCH 2/3] signal: Implement SIL_FAULT_TRAPNO"
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Marco Elver <elver@xxxxxxxxxx> writes:

> On Sat, 1 May 2021 at 00:54, Eric W. Biederman <ebiederm@xxxxxxxxxxxx> wrote:
>>
>> Now that si_trapno is part of the union in _si_fault and available on
>> all architectures, add SIL_FAULT_TRAPNO and update siginfo_layout to
>> return SIL_FAULT_TRAPNO when si_trapno is actually used.
>>
>> Update the code that uses siginfo_layout to deal with SIL_FAULT_TRAPNO
>> and have the same code ignore si_trapno in in all other cases.
>>
>> Signed-off-by: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
>> ---
>> fs/signalfd.c | 7 ++-----
>> include/linux/signal.h | 1 +
>> kernel/signal.c | 36 ++++++++++++++----------------------
>> 3 files changed, 17 insertions(+), 27 deletions(-)
>>
>> diff --git a/fs/signalfd.c b/fs/signalfd.c
>> index 040a1142915f..126c681a30e7 100644
>> --- a/fs/signalfd.c
>> +++ b/fs/signalfd.c
>> @@ -123,15 +123,12 @@ static int signalfd_copyinfo(struct signalfd_siginfo __user *uinfo,
>> */
>> case SIL_FAULT:
>> new.ssi_addr = (long) kinfo->si_addr;
>> -#ifdef __ARCH_SI_TRAPNO
>> + case SIL_FAULT_TRAPNO:
>> + new.ssi_addr = (long) kinfo->si_addr;
>> new.ssi_trapno = kinfo->si_trapno;
>> -#endif
>> break;
>> case SIL_FAULT_MCEERR:
>> new.ssi_addr = (long) kinfo->si_addr;
>> -#ifdef __ARCH_SI_TRAPNO
>> - new.ssi_trapno = kinfo->si_trapno;
>> -#endif
>> new.ssi_addr_lsb = (short) kinfo->si_addr_lsb;
>> break;
>> case SIL_PERF_EVENT:
>> diff --git a/include/linux/signal.h b/include/linux/signal.h
>> index 1e98548d7cf6..5160fd45e5ca 100644
>> --- a/include/linux/signal.h
>> +++ b/include/linux/signal.h
>> @@ -40,6 +40,7 @@ enum siginfo_layout {
>> SIL_TIMER,
>> SIL_POLL,
>> SIL_FAULT,
>> + SIL_FAULT_TRAPNO,
>> SIL_FAULT_MCEERR,
>> SIL_FAULT_BNDERR,
>> SIL_FAULT_PKUERR,
>> diff --git a/kernel/signal.c b/kernel/signal.c
>> index c3017aa8024a..7b2d61cb7411 100644
>> --- a/kernel/signal.c
>> +++ b/kernel/signal.c
>> @@ -1194,6 +1194,7 @@ static inline bool has_si_pid_and_uid(struct kernel_siginfo *info)
>> case SIL_TIMER:
>> case SIL_POLL:
>> case SIL_FAULT:
>> + case SIL_FAULT_TRAPNO:
>> case SIL_FAULT_MCEERR:
>> case SIL_FAULT_BNDERR:
>> case SIL_FAULT_PKUERR:
>> @@ -2527,6 +2528,7 @@ static void hide_si_addr_tag_bits(struct ksignal *ksig)
>> {
>> switch (siginfo_layout(ksig->sig, ksig->info.si_code)) {
>> case SIL_FAULT:
>> + case SIL_FAULT_TRAPNO:
>> case SIL_FAULT_MCEERR:
>> case SIL_FAULT_BNDERR:
>> case SIL_FAULT_PKUERR:
>> @@ -3206,6 +3208,12 @@ enum siginfo_layout siginfo_layout(unsigned sig, int si_code)
>> if ((sig == SIGBUS) &&
>> (si_code >= BUS_MCEERR_AR) && (si_code <= BUS_MCEERR_AO))
>> layout = SIL_FAULT_MCEERR;
>> + else if (IS_ENABLED(ALPHA) &&
>> + ((sig == SIGFPE) ||
>> + ((sig == SIGTRAP) && (si_code == TRAP_UNK))))
>> + layout = SIL_FAULT_TRAPNO;
>> + else if (IS_ENABLED(SPARC) && (sig == SIGILL) && (si_code == ILL_ILLTRP))
>> + layout = SIL_FAULT_TRAPNO;
>
> The breakage isn't apparent here, but in later patches. These need to
> become CONFIG_SPARC and CONFIG_ALPHA.

Good catch. For some reason I thought IS_ENABLED added the CONFIG_
prefix but I looked and it doesn't.

>> else if ((sig == SIGSEGV) && (si_code == SEGV_BNDERR))
>> layout = SIL_FAULT_BNDERR;
>> #ifdef SEGV_PKUERR
>> @@ -3317,30 +3325,22 @@ void copy_siginfo_to_external32(struct compat_siginfo *to,
>> break;
>> case SIL_FAULT:
>> to->si_addr = ptr_to_compat(from->si_addr);
>> -#ifdef __ARCH_SI_TRAPNO
>> + break;
>> + case SIL_FAULT_TRAPNO:
>> + to->si_addr = ptr_to_compat(from->si_addr);
>> to->si_trapno = from->si_trapno;
>> -#endif
>> break;
>> case SIL_FAULT_MCEERR:
>> to->si_addr = ptr_to_compat(from->si_addr);
>> -#ifdef __ARCH_SI_TRAPNO
>> - to->si_trapno = from->si_trapno;
>> -#endif
>> to->si_addr_lsb = from->si_addr_lsb;
>> break;
>> case SIL_FAULT_BNDERR:
>> to->si_addr = ptr_to_compat(from->si_addr);
>> -#ifdef __ARCH_SI_TRAPNO
>> - to->si_trapno = from->si_trapno;
>> -#endif
>> to->si_lower = ptr_to_compat(from->si_lower);
>> to->si_upper = ptr_to_compat(from->si_upper);
>> break;
>> case SIL_FAULT_PKUERR:
>> to->si_addr = ptr_to_compat(from->si_addr);
>> -#ifdef __ARCH_SI_TRAPNO
>> - to->si_trapno = from->si_trapno;
>> -#endif
>> to->si_pkey = from->si_pkey;
>> break;
>> case SIL_PERF_EVENT:
>> @@ -3401,30 +3401,22 @@ static int post_copy_siginfo_from_user32(kernel_siginfo_t *to,
>> break;
>> case SIL_FAULT:
>> to->si_addr = compat_ptr(from->si_addr);
>> -#ifdef __ARCH_SI_TRAPNO
>> + break;
>> + case SIL_FAULT_TRAPNO:
>> + to->si_addr = compat_ptr(from->si_addr);
>> to->si_trapno = from->si_trapno;
>> -#endif
>> break;
>> case SIL_FAULT_MCEERR:
>> to->si_addr = compat_ptr(from->si_addr);
>> -#ifdef __ARCH_SI_TRAPNO
>> - to->si_trapno = from->si_trapno;
>> -#endif
>> to->si_addr_lsb = from->si_addr_lsb;
>> break;
>> case SIL_FAULT_BNDERR:
>> to->si_addr = compat_ptr(from->si_addr);
>> -#ifdef __ARCH_SI_TRAPNO
>> - to->si_trapno = from->si_trapno;
>> -#endif
>> to->si_lower = compat_ptr(from->si_lower);
>> to->si_upper = compat_ptr(from->si_upper);
>> break;
>> case SIL_FAULT_PKUERR:
>> to->si_addr = compat_ptr(from->si_addr);
>> -#ifdef __ARCH_SI_TRAPNO
>> - to->si_trapno = from->si_trapno;
>> -#endif
>> to->si_pkey = from->si_pkey;
>> break;
>> case SIL_PERF_EVENT:
>> --
>> 2.30.1

Next message: Eric W. Biederman: "Re: [PATCH 1/3] siginfo: Move si_trapno inside the union inside _si_fault"
Previous message: Linus Torvalds: "Re: [git pull] work.misc"
In reply to: Marco Elver: "Re: [PATCH 2/3] signal: Implement SIL_FAULT_TRAPNO"
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