| Message ID | alpine.DEB.2.21.1903182130020.28623@digraph.polyomino.org.uk |
|---|---|
| State | New |
| Headers | show |
| Series | Add AArch64 HWCAPs from Linux 5.0 | expand |
On 18/03/2019 21:30, Joseph Myers wrote: > This patch adds new AArch64 HWCAPs from Linux 5.0 to the AArch64 > bits/hwcap.h and dl-procinfo.c. > > Tested (compilation only) with build-many-glibcs.py for > aarch64-linux-gnu. > > 2019-03-18 Joseph Myers <joseph@codesourcery.com> > > * sysdeps/unix/sysv/linux/aarch64/bits/hwcap.h (HWCAP_SB): New > macro. > (HWCAP_PACA): Likewise. > (HWCAP_PACG): Likewise. > * sysdeps/unix/sysv/linux/aarch64/dl-procinfo.c (_DL_HWCAP_COUNT): > Increase to 32. > (_dl_aarch64_cap_flags): Add new entries for new HWCAPs. This is OK. thanks. > diff --git a/sysdeps/unix/sysv/linux/aarch64/bits/hwcap.h b/sysdeps/unix/sysv/linux/aarch64/bits/hwcap.h > index 9a395c597f..5f50623953 100644 > --- a/sysdeps/unix/sysv/linux/aarch64/bits/hwcap.h > +++ b/sysdeps/unix/sysv/linux/aarch64/bits/hwcap.h > @@ -51,3 +51,6 @@ > #define HWCAP_ILRCPC (1 << 26) > #define HWCAP_FLAGM (1 << 27) > #define HWCAP_SSBS (1 << 28) > +#define HWCAP_SB (1 << 29) > +#define HWCAP_PACA (1 << 30) > +#define HWCAP_PACG (1UL << 31) Note: we ran out of 32bit hwcaps, so further flags here would not be compatible with ilp32 auxv. the plan is to introduce hwcap2 and keep adding flags there, however that will require a change in ifunc resolver abi if we want to pass down hwcap2. i will try to come up with a fix for that in this release cycle.
* Szabolcs Nagy: >> diff --git a/sysdeps/unix/sysv/linux/aarch64/bits/hwcap.h >> b/sysdeps/unix/sysv/linux/aarch64/bits/hwcap.h >> index 9a395c597f..5f50623953 100644 >> --- a/sysdeps/unix/sysv/linux/aarch64/bits/hwcap.h >> +++ b/sysdeps/unix/sysv/linux/aarch64/bits/hwcap.h >> @@ -51,3 +51,6 @@ >> #define HWCAP_ILRCPC (1 << 26) >> #define HWCAP_FLAGM (1 << 27) >> #define HWCAP_SSBS (1 << 28) >> +#define HWCAP_SB (1 << 29) >> +#define HWCAP_PACA (1 << 30) >> +#define HWCAP_PACG (1UL << 31) > > Note: we ran out of 32bit hwcaps, so further flags here > would not be compatible with ilp32 auxv. > > the plan is to introduce hwcap2 and keep adding flags > there, however that will require a change in ifunc > resolver abi if we want to pass down hwcap2. > i will try to come up with a fix for that in this > release cycle. Yuck. The last bit should have been used for indicating that additional IFUNC resolver information is available. 8-( Is there still a way to fix this without requiring additional ABI symbols?
On 19/03/2019 14:34, Florian Weimer wrote: > * Szabolcs Nagy: > >>> diff --git a/sysdeps/unix/sysv/linux/aarch64/bits/hwcap.h >>> b/sysdeps/unix/sysv/linux/aarch64/bits/hwcap.h >>> index 9a395c597f..5f50623953 100644 >>> --- a/sysdeps/unix/sysv/linux/aarch64/bits/hwcap.h >>> +++ b/sysdeps/unix/sysv/linux/aarch64/bits/hwcap.h >>> @@ -51,3 +51,6 @@ >>> #define HWCAP_ILRCPC (1 << 26) >>> #define HWCAP_FLAGM (1 << 27) >>> #define HWCAP_SSBS (1 << 28) >>> +#define HWCAP_SB (1 << 29) >>> +#define HWCAP_PACA (1 << 30) >>> +#define HWCAP_PACG (1UL << 31) >> >> Note: we ran out of 32bit hwcaps, so further flags here >> would not be compatible with ilp32 auxv. >> >> the plan is to introduce hwcap2 and keep adding flags >> there, however that will require a change in ifunc >> resolver abi if we want to pass down hwcap2. >> i will try to come up with a fix for that in this >> release cycle. > > Yuck. The last bit should have been used for indicating that > additional IFUNC resolver information is available. 8-( the ilp32 port passes uint64_t hwcap to the resolver currently so the top 32bit can be used by glibc to signal the presence of additional arguments to the resolver (this should work for both lp64 and ilp32) however i havent worked out yet what the additional argument should be (so it's extensible reasonably in the future). > > Is there still a way to fix this without requiring additional ABI > symbols? >
* Szabolcs Nagy: > the ilp32 port passes uint64_t hwcap to the resolver currently > so the top 32bit can be used by glibc to signal the presence > of additional arguments to the resolver (this should work for > both lp64 and ilp32) however i havent worked out yet what > the additional argument should be (so it's extensible reasonably > in the future). It could be a pointer to a struct with the struct size as the first member. That's really simple and could work on other architectures, too. Or we could delay IFUNC resolvers after other relocations, so that IFUNC resolvers can use arbitrary data symbols from the dynamic loader because all data relocations have been processed before they run. Then we won't have to add additional IFUNC resolver arguments ever again, and can use the regular ABI maintenance to deal with compatibility issues.
diff --git a/sysdeps/unix/sysv/linux/aarch64/bits/hwcap.h b/sysdeps/unix/sysv/linux/aarch64/bits/hwcap.h index 9a395c597f..5f50623953 100644 --- a/sysdeps/unix/sysv/linux/aarch64/bits/hwcap.h +++ b/sysdeps/unix/sysv/linux/aarch64/bits/hwcap.h @@ -51,3 +51,6 @@ #define HWCAP_ILRCPC (1 << 26) #define HWCAP_FLAGM (1 << 27) #define HWCAP_SSBS (1 << 28) +#define HWCAP_SB (1 << 29) +#define HWCAP_PACA (1 << 30) +#define HWCAP_PACG (1UL << 31) diff --git a/sysdeps/unix/sysv/linux/aarch64/dl-procinfo.c b/sysdeps/unix/sysv/linux/aarch64/dl-procinfo.c index 30ee7c8176..97cf16fc2d 100644 --- a/sysdeps/unix/sysv/linux/aarch64/dl-procinfo.c +++ b/sysdeps/unix/sysv/linux/aarch64/dl-procinfo.c @@ -57,7 +57,7 @@ PROCINFO_CLASS struct cpu_features _dl_aarch64_cpu_features #endif /* Number of HWCAP bits set. */ -#define _DL_HWCAP_COUNT 29 +#define _DL_HWCAP_COUNT 32 #if !defined PROCINFO_DECL && defined SHARED ._dl_aarch64_cap_flags @@ -69,7 +69,8 @@ PROCINFO_CLASS const char _dl_aarch64_cap_flags[_DL_HWCAP_COUNT][10] = { "fp", "asimd", "evtstrm", "aes", "pmull", "sha1", "sha2", "crc32", "atomics", "fphp", "asimdhp", "cpuid", "asimdrdm", "jscvt", "fcma", "lrcpc", "dcpop", "sha3", "sm3", "sm4", "asimddp", "sha512", "sve", - "asimdfhm", "dit", "uscat", "ilrcpc", "flagm", "ssbs" } + "asimdfhm", "dit", "uscat", "ilrcpc", "flagm", "ssbs", "sb", "paca", + "pacg" } #endif #if !defined SHARED || defined PROCINFO_DECL ;