From patchwork Tue Jun 18 17:31:09 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Adhemerval Zanella X-Patchwork-Id: 33200 X-Patchwork-Delegate: tuliom@linux.vnet.ibm.com Received: (qmail 82615 invoked by alias); 18 Jun 2019 17:31:17 -0000 Mailing-List: contact libc-alpha-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: libc-alpha-owner@sourceware.org Delivered-To: mailing list libc-alpha@sourceware.org Received: (qmail 82604 invoked by uid 89); 18 Jun 2019 17:31:17 -0000 Authentication-Results: sourceware.org; auth=none X-Spam-SWARE-Status: No, score=-21.1 required=5.0 tests=AWL, BAYES_00, GIT_PATCH_0, GIT_PATCH_1, GIT_PATCH_2, GIT_PATCH_3, RCVD_IN_DNSWL_NONE, SPF_PASS autolearn=ham version=3.3.1 spammy=solely X-HELO: mail-ua1-f65.google.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=subject:to:references:from:openpgp:autocrypt:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=s8kAIMsCl5jGX9tQBp7kd7Ta2i88imjS9uqQ0w9KnGo=; b=QYwlTG69pUCG25aep6CXXFi9BW3T86LjmfCW7zNR7vtC6kB5iNYru5tYlBz6ZZCI0M WYNiF2waETlnpUAPmouP0iHChXpBfIFNYbXZNi83GXCqPT1PPINDpp1y+ISM7yKjEy/i ztJ4Cxm5EcFJHc/4VmN/l9rcTo7uKdiBvyUEPXqsRErfQPD6R/RgQU01LxHhZ7AUszhv xyEP68+m66MQCwsiOcb9nqNemK+RVF/JmaHGr/thKZ7XmMAq5Esjd3pTU4TJLri7kd4P jhlwkS6pdOE0DmJX5ifvghlPVyetoh668JyjAWa59QU4VL9egZ0xIOqiUTs7liNW5tgc nKEA== Return-Path: Subject: Re: [PATCH 08/12] powerpc: Refactor vsyscall internal macros To: Tulio Magno Quites Machado Filho , libc-alpha@sourceware.org References: <20190614152908.8101-1-adhemerval.zanella@linaro.org> <20190614152908.8101-8-adhemerval.zanella@linaro.org> <8736k7opc3.fsf@linux.ibm.com> From: Adhemerval Zanella Openpgp: preference=signencrypt Message-ID: <98dd8c2f-4a0f-d571-3f1e-d14c0a741fa7@linaro.org> Date: Tue, 18 Jun 2019 14:31:09 -0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.7.0 MIME-Version: 1.0 In-Reply-To: <8736k7opc3.fsf@linux.ibm.com> On 17/06/2019 18:48, Tulio Magno Quites Machado Filho wrote: > Adhemerval Zanella writes: > >> * sysdeps/unix/sysv/linux/powerpc/dl-vdso.h: New file. >> * sysdeps/unix/sysv/linux/powerpc/get_timebase_freq.c >> (get_timebase_freq_fallback): New symbol. >> (__get_timebase_freq): Call vDSO as a function pointer instead of >> arch-specific macros. >> * .../unix/sysv/linux/powerpc/gettimeofday.c (gettimeofday): Use >> get_vdso_symbol. > > It's the first time a see a ChangeLog entry starting with '\t* ...'. > Is this really valid? > >> diff --git a/sysdeps/unix/sysv/linux/powerpc/sysdep.h b/sysdeps/unix/sysv/linux/powerpc/sysdep.h >> index 20167615c8..cf967a8c33 100644 >> --- a/sysdeps/unix/sysv/linux/powerpc/sysdep.h >> +++ b/sysdeps/unix/sysv/linux/powerpc/sysdep.h >> @@ -32,3 +33,12 @@ >> # define HAVE_SIGTRAMP_32 "__kernel_sigtramp32" >> # define HAVE_SIGTRAMP_RT32 "__kernel_sigtramp_rt32" >> #endif >> + >> +#ifndef __ASSEMBLER__ >> + >> +/* PowerPC vDSO symbols always succeed, so there is no need to emulate a >> + function call and check for CR0.SO value. */ >> +#define INTERNAL_VSYSCALL_CALL(funcptr, err, nr, args...) \ >> + ({ err = 0; funcptr (args); }) > > After applying this patch, rt/cpu-clock1 started to fail with: > > clock_gettime on reaped PID 26033 clock fffffffffffcd272 => Success > clock_getres on reaped PID 26033 clock fffffffffffcd272 => Success > > Both cases are expecting to receive errno = EINVAL instead of Success. > > Isn't CR0.SO important? > > Reference: > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/powerpc/kernel/vdso64/gettimeofday.S#n190 > In fact we can't really remove the CR0.SO check because the vDSO symbol might itself fallback to a syscall (the case of rt/cpu-clock1 where is check for invalid clockid). The vDSO simplification turned out to be less than I expected, but it is moving towards consolidate the time and gettimeofday. Updated patch below. Reviewed-by: Tulio Magno Quites Machado Filho --- Subject: [PATCH 08/12] powerpc: Simplify vsyscall internal macros This patch simplifies the powerpc internal macros for vDSO calls by: - Removing INTERNAL_VSYSCALL_NO_SYSCALL_FALLBACK, used solely on get_timebase_freq. - Adjust INTERNAL_VSYSCALL_CALL_TYPE powerpc32 to follow powerpc64 argument ordering. - Use HAVE_*_VSYSCALL instead of explicit strings. - Make powerpc libc-vdso.h include generic implementation. No semantic change expected, checked on powerpc-linux-gnu-power4, powerpc64-linux-gnu, and powerpc64le-linux-gnu. * sysdeps/unix/sysv/linux/libc-vdso.h (VDSO_IFUNC_RET): Define if not defined. * sysdeps/unix/sysv/linux/powerpc/get_timebase_freq.c (__get_timebase_freq): Remove use of INTERNAL_VSYSCALL_NO_SYSCALL_FALLBACK. (get_timebase_freq_fallback): New symbol. * sysdeps/unix/sysv/linux/powerpc/gettimeofday.c (time): Use HAVE_GETTIMEOFDAY_VSYSCALL. * sysdeps/unix/sysv/linux/powerpc/time.c (gettimeofday): Use HAVE_TIME_VSYSCALL. * sysdeps/unix/sysv/linux/powerpc/libc-vdso.h: Include generic implementation. * sysdeps/unix/sysv/linux/powerpc/powerpc32/sysdep.h (INTERNAL_VSYSCALL_CALL_TYPE): Make calling convention similar to powerpc64. (INTERNAL_VSYSCALL_NO_SYSCALL_FALLBACK): Remove macro. * .../sysv/linux/powerpc/powerpc64/sysdep.h (INTERNAL_VSYSCALL_NO_SYSCALL_FALLBACK): Likewise. * sysdeps/unix/sysv/linux/powerpc/sysdep.h (HAVE_GETTIMEOFDAY_VSYSCALL): Define. --- sysdeps/unix/sysv/linux/libc-vdso.h | 7 ++++++ .../sysv/linux/powerpc/get_timebase_freq.c | 24 ++++++++++++------- .../unix/sysv/linux/powerpc/gettimeofday.c | 2 +- sysdeps/unix/sysv/linux/powerpc/libc-vdso.h | 24 ++++++++++--------- .../sysv/linux/powerpc/powerpc32/sysdep.h | 18 ++------------ .../sysv/linux/powerpc/powerpc64/sysdep.h | 19 +-------------- sysdeps/unix/sysv/linux/powerpc/sysdep.h | 1 + sysdeps/unix/sysv/linux/powerpc/time.c | 2 +- 8 files changed, 41 insertions(+), 56 deletions(-) diff --git a/sysdeps/unix/sysv/linux/libc-vdso.h b/sysdeps/unix/sysv/linux/libc-vdso.h index f681868137..199ae9a033 100644 --- a/sysdeps/unix/sysv/linux/libc-vdso.h +++ b/sysdeps/unix/sysv/linux/libc-vdso.h @@ -21,6 +21,13 @@ #define VDSO_SYMBOL(__name) __vdso_##__name +/* Adjust the return IFUNC value from a vDSO symbol accordingly required + architecture ABI. It is used for powerpc64 elfv1 to create a ODP + entry since kernvel vDSO does not provide it. */ +#ifndef VDSO_IFUNC_RET +# define VDSO_IFUNC_RET(__value) (__value) +#endif + #ifdef HAVE_CLOCK_GETTIME_VSYSCALL extern int (*VDSO_SYMBOL(clock_gettime)) (clockid_t, struct timespec *); #endif diff --git a/sysdeps/unix/sysv/linux/powerpc/get_timebase_freq.c b/sysdeps/unix/sysv/linux/powerpc/get_timebase_freq.c index 23e7694d87..57eb0e19d9 100644 --- a/sysdeps/unix/sysv/linux/powerpc/get_timebase_freq.c +++ b/sysdeps/unix/sysv/linux/powerpc/get_timebase_freq.c @@ -23,17 +23,11 @@ #include #include -uint64_t -__get_timebase_freq (void) +static uint64_t +get_timebase_freq_fallback (void) { hp_timing_t result = 0L; -#ifdef SHARED - /* The vDSO does not return an error (it clear cr0.so on returning). */ - INTERNAL_SYSCALL_DECL (err); - result = - INTERNAL_VSYSCALL_NO_SYSCALL_FALLBACK (get_tbfreq, err, uint64_t, 0); -#else /* We read the information from the /proc filesystem. /proc/cpuinfo contains at least one line like: timebase : 33333333 @@ -99,8 +93,20 @@ __get_timebase_freq (void) } } } -#endif return result; } + +uint64_t +__get_timebase_freq (void) +{ + /* The vDSO does not have a fallback mechanism (such calling a syscall). */ + __typeof (VDSO_SYMBOL (get_tbfreq)) vdsop = VDSO_SYMBOL (get_tbfreq); + PTR_DEMANGLE (vdsop); + if (vdsop == NULL) + return get_timebase_freq_fallback (); + + INTERNAL_SYSCALL_DECL (err); + return INTERNAL_VSYSCALL_CALL_TYPE (vdsop, err, uint64_t, 0); +} weak_alias (__get_timebase_freq, __ppc_get_timebase_freq) diff --git a/sysdeps/unix/sysv/linux/powerpc/gettimeofday.c b/sysdeps/unix/sysv/linux/powerpc/gettimeofday.c index 6b92e2807b..47859abf7a 100644 --- a/sysdeps/unix/sysv/linux/powerpc/gettimeofday.c +++ b/sysdeps/unix/sysv/linux/powerpc/gettimeofday.c @@ -58,7 +58,7 @@ __gettimeofday_syscall (struct timeval *tv, struct timezone *tz) } # define INIT_ARCH() \ - void *vdso_gettimeofday = get_vdso_symbol ("__kernel_gettimeofday") + void *vdso_gettimeofday = get_vdso_symbol (HAVE_GETTIMEOFDAY_VSYSCALL) /* If the vDSO is not available we fall back syscall. */ diff --git a/sysdeps/unix/sysv/linux/powerpc/libc-vdso.h b/sysdeps/unix/sysv/linux/powerpc/libc-vdso.h index 47e925493b..170adcc964 100644 --- a/sysdeps/unix/sysv/linux/powerpc/libc-vdso.h +++ b/sysdeps/unix/sysv/linux/powerpc/libc-vdso.h @@ -22,17 +22,9 @@ #include #include -#include_next - -extern unsigned long long (*VDSO_SYMBOL(get_tbfreq)) (void); -#if defined(__PPC64__) || defined(__powerpc64__) -extern void *VDSO_SYMBOL(sigtramp_rt64); -#else -extern void *VDSO_SYMBOL(sigtramp32); -extern void *VDSO_SYMBOL(sigtramp_rt32); -#endif #if (defined(__PPC64__) || defined(__powerpc64__)) && _CALL_ELF != 2 +# include /* The correct solution is for _dl_vdso_vsym to return the address of the OPD for the kernel VDSO function. That address would then be stored in the __vdso_* variables and returned as the result of the IFUNC resolver function. @@ -51,7 +43,7 @@ extern void *VDSO_SYMBOL(sigtramp_rt32); are processed immediately at startup the resolver functions and this code need not be thread-safe, but if the caller writes to a PLT slot it must do so in a thread-safe manner with all the required barriers. */ -#define VDSO_IFUNC_RET(value) \ +# define VDSO_IFUNC_RET(value) \ ({ \ static Elf64_FuncDesc vdso_opd = { .fd_toc = ~0x0 }; \ vdso_opd.fd_func = (Elf64_Addr)value; \ @@ -59,7 +51,17 @@ extern void *VDSO_SYMBOL(sigtramp_rt32); }) #else -#define VDSO_IFUNC_RET(value) ((void *) (value)) +# define VDSO_IFUNC_RET(value) ((void *) (value)) +#endif + +#include_next + +extern unsigned long long (*VDSO_SYMBOL(get_tbfreq)) (void); +#if defined(__PPC64__) || defined(__powerpc64__) +extern void *VDSO_SYMBOL(sigtramp_rt64); +#else +extern void *VDSO_SYMBOL(sigtramp32); +extern void *VDSO_SYMBOL(sigtramp_rt32); #endif #endif /* _LIBC_VDSO_H */ diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc32/sysdep.h b/sysdeps/unix/sysv/linux/powerpc/powerpc32/sysdep.h index f459543fcd..703c668a92 100644 --- a/sysdeps/unix/sysv/linux/powerpc/powerpc32/sysdep.h +++ b/sysdeps/unix/sysv/linux/powerpc/powerpc32/sysdep.h @@ -41,7 +41,7 @@ function call, with the exception of LR (which is needed for the "sc; bnslr+" sequence) and CR (where only CR0.SO is clobbered to signal an error return status). */ -# define INTERNAL_VSYSCALL_CALL_TYPE(funcptr, err, nr, type, args...) \ +# define INTERNAL_VSYSCALL_CALL_TYPE(funcptr, err, type, nr, args...) \ ({ \ register void *r0 __asm__ ("r0"); \ register long int r3 __asm__ ("r3"); \ @@ -69,7 +69,7 @@ }) #define INTERNAL_VSYSCALL_CALL(funcptr, err, nr, args...) \ - INTERNAL_VSYSCALL_CALL_TYPE(funcptr, err, nr, long int, args) + INTERNAL_VSYSCALL_CALL_TYPE(funcptr, err, long int, nr, args) # undef INLINE_SYSCALL # define INLINE_SYSCALL(name, nr, args...) \ @@ -131,20 +131,6 @@ # undef INTERNAL_SYSCALL_ERRNO # define INTERNAL_SYSCALL_ERRNO(val, err) (val) -# define INTERNAL_VSYSCALL_NO_SYSCALL_FALLBACK(name, err, type, nr, args...) \ - ({ \ - type sc_ret = ENOSYS; \ - \ - __typeof (__vdso_##name) vdsop = __vdso_##name; \ - PTR_DEMANGLE (vdsop); \ - if (vdsop != NULL) \ - sc_ret = \ - INTERNAL_VSYSCALL_CALL_TYPE (vdsop, err, nr, type, ##args); \ - else \ - err = 1 << 28; \ - sc_ret; \ - }) - # define LOADARGS_0(name, dummy) \ r0 = name # define LOADARGS_1(name, __arg1) \ diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc64/sysdep.h b/sysdeps/unix/sysv/linux/powerpc/powerpc64/sysdep.h index 06222f52e6..e7b2fce05f 100644 --- a/sysdeps/unix/sysv/linux/powerpc/powerpc64/sysdep.h +++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/sysdep.h @@ -45,22 +45,6 @@ #endif /* __ASSEMBLER__ */ -/* This version is for internal uses when there is no desire - to set errno */ -#define INTERNAL_VSYSCALL_NO_SYSCALL_FALLBACK(name, err, type, nr, args...) \ - ({ \ - type sc_ret = ENOSYS; \ - \ - __typeof (__vdso_##name) vdsop = __vdso_##name; \ - PTR_DEMANGLE (vdsop); \ - if (vdsop != NULL) \ - sc_ret = \ - INTERNAL_VSYSCALL_CALL_TYPE (vdsop, err, type, nr, ##args); \ - else \ - err = 1 << 28; \ - sc_ret; \ - }) - /* Define a macro which expands inline into the wrapper code for a system call. This use is for internal calls that do not need to handle errors normally. It will never touch errno. This returns just what the kernel @@ -94,10 +78,9 @@ #define INTERNAL_VSYSCALL_CALL(funcptr, err, nr, args...) \ INTERNAL_VSYSCALL_CALL_TYPE(funcptr, err, long int, nr, args) -#undef INLINE_SYSCALL - /* This version is for kernels that implement system calls that behave like function calls as far as register saving. */ +#undef INLINE_SYSCALL #define INLINE_SYSCALL(name, nr, args...) \ ({ \ INTERNAL_SYSCALL_DECL (sc_err); \ diff --git a/sysdeps/unix/sysv/linux/powerpc/sysdep.h b/sysdeps/unix/sysv/linux/powerpc/sysdep.h index 20167615c8..357d1b5243 100644 --- a/sysdeps/unix/sysv/linux/powerpc/sysdep.h +++ b/sysdeps/unix/sysv/linux/powerpc/sysdep.h @@ -24,6 +24,7 @@ #define HAVE_CLOCK_GETTIME_VSYSCALL "__kernel_clock_gettime" #define HAVE_GETCPU_VSYSCALL "__kernel_getcpu" #define HAVE_TIME_VSYSCALL "__kernel_time" +#define HAVE_GETTIMEOFDAY_VSYSCALL "__kernel_gettimeofday" #define HAVE_GET_TBFREQ "__kernel_get_tbfreq" #if defined(__PPC64__) || defined(__powerpc64__) diff --git a/sysdeps/unix/sysv/linux/powerpc/time.c b/sysdeps/unix/sysv/linux/powerpc/time.c index 53fd119b00..4856da0862 100644 --- a/sysdeps/unix/sysv/linux/powerpc/time.c +++ b/sysdeps/unix/sysv/linux/powerpc/time.c @@ -67,7 +67,7 @@ time_syscall (time_t *t) } # define INIT_ARCH() \ - void *vdso_time = get_vdso_symbol ("__kernel_time"); + void *vdso_time = get_vdso_symbol (HAVE_TIME_VSYSCALL); /* If the vDSO is not available we fall back to the syscall. */ libc_ifunc_hidden (__redirect_time, time,