| From be7273225698074347a71de58006977bb304d7f7 Mon Sep 17 00:00:00 2001 |
| From: Khem Raj <raj.khem@gmail.com> |
| Date: Wed, 18 Mar 2015 00:53:47 +0000 |
| Subject: [PATCH 22/27] eglibc: Clear cache lines on ppc8xx |
| |
| 2007-06-13 Nathan Sidwell <nathan@codesourcery.com> |
| Mark Shinwell <shinwell@codesourcery.com> |
| |
| * sysdeps/unix/sysv/linux/powerpc/libc-start.c |
| (__libc_start_main): Detect 8xx parts and clear |
| __cache_line_size if detected. |
| * sysdeps/unix/sysv/linux/powerpc/dl-sysdep.c |
| (DL_PLATFORM_AUXV): Likewise. |
| |
| Upstream-Status: Pending |
| Signed-off-by: Khem Raj <raj.khem@gmail.com> |
| --- |
| sysdeps/unix/sysv/linux/powerpc/dl-sysdep.c | 14 +++++++++++++- |
| sysdeps/unix/sysv/linux/powerpc/libc-start.c | 15 ++++++++++++++- |
| 2 files changed, 27 insertions(+), 2 deletions(-) |
| |
| diff --git a/sysdeps/unix/sysv/linux/powerpc/dl-sysdep.c b/sysdeps/unix/sysv/linux/powerpc/dl-sysdep.c |
| index c2504ff..d50f1cb 100644 |
| --- a/sysdeps/unix/sysv/linux/powerpc/dl-sysdep.c |
| +++ b/sysdeps/unix/sysv/linux/powerpc/dl-sysdep.c |
| @@ -24,9 +24,21 @@ int __cache_line_size attribute_hidden; |
| /* Scan the Aux Vector for the "Data Cache Block Size" entry. If found |
| verify that the static extern __cache_line_size is defined by checking |
| for not NULL. If it is defined then assign the cache block size |
| - value to __cache_line_size. */ |
| + value to __cache_line_size. This is used by memset to |
| + optimize setting to zero. We have to detect 8xx processors, which |
| + have buggy dcbz implementations that cannot report page faults |
| + correctly. That requires reading SPR, which is a privileged |
| + operation. Fortunately 2.2.18 and later emulates PowerPC mfspr |
| + reads from the PVR register. */ |
| #define DL_PLATFORM_AUXV \ |
| case AT_DCACHEBSIZE: \ |
| + if (__LINUX_KERNEL_VERSION >= 0x020218) \ |
| + { \ |
| + unsigned pvr = 0; \ |
| + asm ("mfspr %0, 287" : "=r" (pvr)); \ |
| + if ((pvr & 0xffff0000) == 0x00500000) \ |
| + break; \ |
| + } \ |
| __cache_line_size = av->a_un.a_val; \ |
| break; |
| |
| diff --git a/sysdeps/unix/sysv/linux/powerpc/libc-start.c b/sysdeps/unix/sysv/linux/powerpc/libc-start.c |
| index a9364c7..a3ed1d4 100644 |
| --- a/sysdeps/unix/sysv/linux/powerpc/libc-start.c |
| +++ b/sysdeps/unix/sysv/linux/powerpc/libc-start.c |
| @@ -68,11 +68,24 @@ __libc_start_main (int argc, char **argv, |
| rtld_fini = NULL; |
| } |
| |
| - /* Initialize the __cache_line_size variable from the aux vector. */ |
| + /* Initialize the __cache_line_size variable from the aux vector. |
| + This is used by memset to optimize setting to zero. We have to |
| + detect 8xx processors, which have buggy dcbz implementations that |
| + cannot report page faults correctly. That requires reading SPR, |
| + which is a privileged operation. Fortunately 2.2.18 and later |
| + emulates PowerPC mfspr reads from the PVR register. */ |
| for (ElfW (auxv_t) * av = auxvec; av->a_type != AT_NULL; ++av) |
| switch (av->a_type) |
| { |
| case AT_DCACHEBSIZE: |
| + if (__LINUX_KERNEL_VERSION >= 0x020218) |
| + { |
| + unsigned pvr = 0; |
| + |
| + asm ("mfspr %0, 287" : "=r" (pvr) :); |
| + if ((pvr & 0xffff0000) == 0x00500000) |
| + break; |
| + } |
| __cache_line_size = av->a_un.a_val; |
| break; |
| } |
| -- |
| 2.1.4 |
| |