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| author | Goran Ferenc <goran.ferenc@imgtec.com> | 2017-06-28 17:55:30 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@google.com> | 2018-02-05 08:58:32 -0800 |
| commit | 491fef35384656b5e11f3bf4ea21693b7a3cc9e4 (patch) | |
| tree | 7a773ebcd97ee1ab2b1f52155b0b539221958404 /arch | |
| parent | 3ab7b67564de5335868033205bd11cdfa7da4377 (diff) | |
UPSTREAM: MIPS: VDSO: Add implementation of gettimeofday() fallback
This patch adds gettimeofday_fallback() function that wraps assembly
invocation of gettimeofday() syscall using __NR_gettimeofday.
This function is used if pure VDSO implementation gettimeofday()
does not succeed for any reason. Its imeplementation is enclosed in
"#ifdef CONFIG_MIPS_CLOCK_VSYSCALL" to be in sync with the similar
arrangement for __vdso_gettimeofday().
If syscall invocation via __NR_gettimeofday fails, register a3 will
be set. So, after the syscall, register a3 is tested and the return
valuem is negated if it's set.
Signed-off-by: Goran Ferenc <goran.ferenc@imgtec.com>
Signed-off-by: Miodrag Dinic <miodrag.dinic@imgtec.com>
Signed-off-by: Aleksandar Markovic <aleksandar.markovic@imgtec.com>
Cc: Douglas Leung <douglas.leung@imgtec.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Petar Jovanovic <petar.jovanovic@imgtec.com>
Cc: Raghu Gandham <raghu.gandham@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/16640/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
(cherry picked from commit 0b523a85e134d41f57ddd8c5193bd9f0a5e20b0d)
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/mips/vdso/gettimeofday.c | 24 |
1 files changed, 23 insertions, 1 deletions
diff --git a/arch/mips/vdso/gettimeofday.c b/arch/mips/vdso/gettimeofday.c index 5f6337545ee2..23305bf6c7a2 100644 --- a/arch/mips/vdso/gettimeofday.c +++ b/arch/mips/vdso/gettimeofday.c @@ -20,6 +20,28 @@ #include <asm/unistd.h> #include <asm/vdso.h> +#ifdef CONFIG_MIPS_CLOCK_VSYSCALL + +static __always_inline long gettimeofday_fallback(struct timeval *_tv, + struct timezone *_tz) +{ + register struct timezone *tz asm("a1") = _tz; + register struct timeval *tv asm("a0") = _tv; + register long ret asm("v0"); + register long nr asm("v0") = __NR_gettimeofday; + register long error asm("a3"); + + asm volatile( + " syscall\n" + : "=r" (ret), "=r" (error) + : "r" (tv), "r" (tz), "r" (nr) + : "memory"); + + return error ? -ret : ret; +} + +#endif + static __always_inline long clock_gettime_fallback(clockid_t _clkid, struct timespec *_ts) { @@ -205,7 +227,7 @@ int __vdso_gettimeofday(struct timeval *tv, struct timezone *tz) ret = do_realtime(&ts, data); if (ret) - return ret; + return gettimeofday_fallback(tv, tz); if (tv) { tv->tv_sec = ts.tv_sec; |