Message ID | 20230526080315.83424-3-martin@martin.st |
---|---|
State | New |
Headers | show |
Series | [FFmpeg-devel,1/4] configure: aarch64: Support assembling the dotprod and i8mm arch extensions | expand |
Context | Check | Description |
---|---|---|
yinshiyou/make_loongarch64 | success | Make finished |
yinshiyou/make_fate_loongarch64 | success | Make fate finished |
andriy/make_x86 | success | Make finished |
andriy/make_fate_x86 | success | Make fate finished |
Le perjantaina 26. toukokuuta 2023, 11.03.14 EEST Martin Storsjö a écrit : > Based on code by Janne Grunau. > > Using HWCAP_CPUID for user space access to the CPU feature registers. See > https://www.kernel.org/doc/html/latest/arm64/cpu-feature-registers.html. > --- > configure | 2 ++ > libavutil/aarch64/cpu.c | 38 ++++++++++++++++++++++++++++++++++++++ > 2 files changed, 40 insertions(+) > > diff --git a/configure b/configure > index 3c7473efb2..b5357b8d27 100755 > --- a/configure > +++ b/configure > @@ -2207,6 +2207,7 @@ HAVE_LIST_PUB=" > > HEADERS_LIST=" > arpa_inet_h > + asm_hwcap_h > asm_types_h > cdio_paranoia_h > cdio_paranoia_paranoia_h > @@ -6422,6 +6423,7 @@ check_headers io.h > enabled libdrm && > check_headers linux/dma-buf.h > > +check_headers asm/hwcap.h > check_headers linux/perf_event.h > check_headers libcrystalhd/libcrystalhd_if.h > check_headers malloc.h > diff --git a/libavutil/aarch64/cpu.c b/libavutil/aarch64/cpu.c > index 42b33e4a2d..34c838c2f5 100644 > --- a/libavutil/aarch64/cpu.c > +++ b/libavutil/aarch64/cpu.c > @@ -20,6 +20,42 @@ > #include "libavutil/cpu_internal.h" > #include "config.h" > > +#if (defined(__linux__) || defined(__ANDROID__)) && HAVE_GETAUXVAL && > HAVE_ASM_HWCAP_H +#include <stdint.h> > +#include <asm/hwcap.h> > +#include <sys/auxv.h> > + > +#define get_cpu_feature_reg(reg, val) \ > + __asm__("mrs %0, " #reg : "=r" (val)) Strictly speaking, this can read any system register. One way to prevent that would be to include the ID_ prefix and _EL1 suffix in the macro. I would have used a pure static inline instead, but that's just a matter of taste. > + > +static int detect_flags(void) > +{ > + unsigned long ret = getauxval(AT_HWCAP); > + int flags = 0; > +#if defined(HWCAP_CPUID) > + uint64_t tmp; > + if (!(ret & HWCAP_CPUID)) > + return flags; > + get_cpu_feature_reg(ID_AA64ISAR0_EL1, tmp); > + if (((tmp >> 44) & 0xf) == 0x1) > + flags |= AV_CPU_FLAG_DOTPROD; > + get_cpu_feature_reg(ID_AA64ISAR1_EL1, tmp); > + if (((tmp >> 52) & 0xf) == 0x1) > + flags |= AV_CPU_FLAG_I8MM; > +#endif NEON detection could be added here, though I've yet to see an Armv8 implementation without AdvSIMD. FWIW, DotProd is exposed as HWCAP_ASIMDDP and I8MM is exposed via HWCAP2_I8MM, using trapped ID registers is not (yet) necessary. > + > + return flags; > +} > + > +#else > + > +static int detect_flags(void) > +{ > + return 0; > +} > + > +#endif > + > int ff_get_cpu_flags_aarch64(void) > { > int flags = AV_CPU_FLAG_ARMV8 * HAVE_ARMV8 | > @@ -33,6 +69,8 @@ int ff_get_cpu_flags_aarch64(void) > flags |= AV_CPU_FLAG_I8MM; > #endif > > + flags |= detect_flags(); > + > return flags; > }
On Sat, 27 May 2023, Rémi Denis-Courmont wrote: > Le perjantaina 26. toukokuuta 2023, 11.03.14 EEST Martin Storsjö a écrit : >> Based on code by Janne Grunau. >> >> Using HWCAP_CPUID for user space access to the CPU feature registers. See >> https://www.kernel.org/doc/html/latest/arm64/cpu-feature-registers.html. >> --- >> configure | 2 ++ >> libavutil/aarch64/cpu.c | 38 ++++++++++++++++++++++++++++++++++++++ >> 2 files changed, 40 insertions(+) >> >> diff --git a/configure b/configure >> index 3c7473efb2..b5357b8d27 100755 >> --- a/configure >> +++ b/configure >> @@ -2207,6 +2207,7 @@ HAVE_LIST_PUB=" >> >> HEADERS_LIST=" >> arpa_inet_h >> + asm_hwcap_h >> asm_types_h >> cdio_paranoia_h >> cdio_paranoia_paranoia_h >> @@ -6422,6 +6423,7 @@ check_headers io.h >> enabled libdrm && >> check_headers linux/dma-buf.h >> >> +check_headers asm/hwcap.h >> check_headers linux/perf_event.h >> check_headers libcrystalhd/libcrystalhd_if.h >> check_headers malloc.h >> diff --git a/libavutil/aarch64/cpu.c b/libavutil/aarch64/cpu.c >> index 42b33e4a2d..34c838c2f5 100644 >> --- a/libavutil/aarch64/cpu.c >> +++ b/libavutil/aarch64/cpu.c >> @@ -20,6 +20,42 @@ >> #include "libavutil/cpu_internal.h" >> #include "config.h" >> >> +#if (defined(__linux__) || defined(__ANDROID__)) && HAVE_GETAUXVAL && >> HAVE_ASM_HWCAP_H +#include <stdint.h> >> +#include <asm/hwcap.h> >> +#include <sys/auxv.h> >> + >> +#define get_cpu_feature_reg(reg, val) \ >> + __asm__("mrs %0, " #reg : "=r" (val)) > > Strictly speaking, this can read any system register. One way to prevent that > would be to include the ID_ prefix and _EL1 suffix in the macro. I would have > used a pure static inline instead, but that's just a matter of taste. > >> + >> +static int detect_flags(void) >> +{ >> + unsigned long ret = getauxval(AT_HWCAP); >> + int flags = 0; >> +#if defined(HWCAP_CPUID) >> + uint64_t tmp; >> + if (!(ret & HWCAP_CPUID)) >> + return flags; >> + get_cpu_feature_reg(ID_AA64ISAR0_EL1, tmp); >> + if (((tmp >> 44) & 0xf) == 0x1) >> + flags |= AV_CPU_FLAG_DOTPROD; >> + get_cpu_feature_reg(ID_AA64ISAR1_EL1, tmp); >> + if (((tmp >> 52) & 0xf) == 0x1) >> + flags |= AV_CPU_FLAG_I8MM; >> +#endif > > NEON detection could be added here, though I've yet to see an Armv8 > implementation without AdvSIMD. I guess we could, but as it's part of the require baseline for armv8-a I don't think there's much need for it? If configured with --disable-neon we don't return that cpuflag though. > FWIW, DotProd is exposed as HWCAP_ASIMDDP and I8MM is exposed via > HWCAP2_I8MM, using trapped ID registers is not (yet) necessary. Ah, I see. I guess using those would be more straightforward. OTOH, HWCAP_CPUID is available much earlier than HWCAP_ASIMDDP or HWCAP2_I8MM (I do some amount of cross building with a fairly old sysroot). I'll think about it, whether it's worth complicating things to try both approaches, or if we should just go with the plain HWCAPs here. // Martin
Le lauantaina 27. toukokuuta 2023, 23.35.14 EEST Martin Storsjö a écrit : > > NEON detection could be added here, though I've yet to see an Armv8 > > implementation without AdvSIMD. > > I guess we could, but as it's part of the require baseline for armv8-a I > don't think there's much need for it? I mean that if you have 95% of the code needed, you might as well add the last 5%. I don't think it's used by much anything. > If configured with --disable-neon we > don't return that cpuflag though. > > > FWIW, DotProd is exposed as HWCAP_ASIMDDP and I8MM is exposed via > > HWCAP2_I8MM, using trapped ID registers is not (yet) necessary. > > Ah, I see. I guess using those would be more straightforward. > > OTOH, HWCAP_CPUID is available much earlier than HWCAP_ASIMDDP or > HWCAP2_I8MM (I do some amount of cross building with a fairly old > sysroot). If the sysroot shares the not-too-old kernel of the host, then ID registers will work anyway. The age of the userspace toolchain affects availability of HWCAP constant definitions, not that of ID registers, which is a purely in- kernel feature. > I'll think about it, whether it's worth complicating things to > try both approaches, or if we should just go with the plain HWCAPs here. I don't really mind either way.
diff --git a/configure b/configure index 3c7473efb2..b5357b8d27 100755 --- a/configure +++ b/configure @@ -2207,6 +2207,7 @@ HAVE_LIST_PUB=" HEADERS_LIST=" arpa_inet_h + asm_hwcap_h asm_types_h cdio_paranoia_h cdio_paranoia_paranoia_h @@ -6422,6 +6423,7 @@ check_headers io.h enabled libdrm && check_headers linux/dma-buf.h +check_headers asm/hwcap.h check_headers linux/perf_event.h check_headers libcrystalhd/libcrystalhd_if.h check_headers malloc.h diff --git a/libavutil/aarch64/cpu.c b/libavutil/aarch64/cpu.c index 42b33e4a2d..34c838c2f5 100644 --- a/libavutil/aarch64/cpu.c +++ b/libavutil/aarch64/cpu.c @@ -20,6 +20,42 @@ #include "libavutil/cpu_internal.h" #include "config.h" +#if (defined(__linux__) || defined(__ANDROID__)) && HAVE_GETAUXVAL && HAVE_ASM_HWCAP_H +#include <stdint.h> +#include <asm/hwcap.h> +#include <sys/auxv.h> + +#define get_cpu_feature_reg(reg, val) \ + __asm__("mrs %0, " #reg : "=r" (val)) + +static int detect_flags(void) +{ + unsigned long ret = getauxval(AT_HWCAP); + int flags = 0; +#if defined(HWCAP_CPUID) + uint64_t tmp; + if (!(ret & HWCAP_CPUID)) + return flags; + get_cpu_feature_reg(ID_AA64ISAR0_EL1, tmp); + if (((tmp >> 44) & 0xf) == 0x1) + flags |= AV_CPU_FLAG_DOTPROD; + get_cpu_feature_reg(ID_AA64ISAR1_EL1, tmp); + if (((tmp >> 52) & 0xf) == 0x1) + flags |= AV_CPU_FLAG_I8MM; +#endif + + return flags; +} + +#else + +static int detect_flags(void) +{ + return 0; +} + +#endif + int ff_get_cpu_flags_aarch64(void) { int flags = AV_CPU_FLAG_ARMV8 * HAVE_ARMV8 | @@ -33,6 +69,8 @@ int ff_get_cpu_flags_aarch64(void) flags |= AV_CPU_FLAG_I8MM; #endif + flags |= detect_flags(); + return flags; }