| Patrick Williams | d8c66bc | 2016-06-20 12:57:21 -0500 | [diff] [blame] | 1 | From b74e34e6f53816ad57b13ba6fd70a97db1bc1eae Mon Sep 17 00:00:00 2001 |
| 2 | From: Khem Raj <raj.khem@gmail.com> |
| 3 | Date: Thu, 31 Dec 2015 15:15:09 -0800 |
| 4 | Subject: [PATCH 21/24] eglibc: Clear cache lines on ppc8xx |
| 5 | |
| 6 | 2007-06-13 Nathan Sidwell <nathan@codesourcery.com> |
| 7 | Mark Shinwell <shinwell@codesourcery.com> |
| 8 | |
| 9 | * sysdeps/unix/sysv/linux/powerpc/libc-start.c |
| 10 | (__libc_start_main): Detect 8xx parts and clear |
| 11 | __cache_line_size if detected. |
| 12 | * sysdeps/unix/sysv/linux/powerpc/dl-sysdep.c |
| 13 | (DL_PLATFORM_AUXV): Likewise. |
| 14 | |
| 15 | Upstream-Status: Pending |
| 16 | |
| 17 | Signed-off-by: Khem Raj <raj.khem@gmail.com> |
| 18 | --- |
| 19 | sysdeps/unix/sysv/linux/powerpc/dl-sysdep.c | 14 +++++++++++++- |
| 20 | sysdeps/unix/sysv/linux/powerpc/libc-start.c | 16 +++++++++++++++- |
| 21 | 2 files changed, 28 insertions(+), 2 deletions(-) |
| 22 | |
| 23 | diff --git a/sysdeps/unix/sysv/linux/powerpc/dl-sysdep.c b/sysdeps/unix/sysv/linux/powerpc/dl-sysdep.c |
| 24 | index c2504ff..d50f1cb 100644 |
| 25 | --- a/sysdeps/unix/sysv/linux/powerpc/dl-sysdep.c |
| 26 | +++ b/sysdeps/unix/sysv/linux/powerpc/dl-sysdep.c |
| 27 | @@ -24,9 +24,21 @@ int __cache_line_size attribute_hidden; |
| 28 | /* Scan the Aux Vector for the "Data Cache Block Size" entry. If found |
| 29 | verify that the static extern __cache_line_size is defined by checking |
| 30 | for not NULL. If it is defined then assign the cache block size |
| 31 | - value to __cache_line_size. */ |
| 32 | + value to __cache_line_size. This is used by memset to |
| 33 | + optimize setting to zero. We have to detect 8xx processors, which |
| 34 | + have buggy dcbz implementations that cannot report page faults |
| 35 | + correctly. That requires reading SPR, which is a privileged |
| 36 | + operation. Fortunately 2.2.18 and later emulates PowerPC mfspr |
| 37 | + reads from the PVR register. */ |
| 38 | #define DL_PLATFORM_AUXV \ |
| 39 | case AT_DCACHEBSIZE: \ |
| 40 | + if (__LINUX_KERNEL_VERSION >= 0x020218) \ |
| 41 | + { \ |
| 42 | + unsigned pvr = 0; \ |
| 43 | + asm ("mfspr %0, 287" : "=r" (pvr)); \ |
| 44 | + if ((pvr & 0xffff0000) == 0x00500000) \ |
| 45 | + break; \ |
| 46 | + } \ |
| 47 | __cache_line_size = av->a_un.a_val; \ |
| 48 | break; |
| 49 | |
| 50 | diff --git a/sysdeps/unix/sysv/linux/powerpc/libc-start.c b/sysdeps/unix/sysv/linux/powerpc/libc-start.c |
| 51 | index 209a16d..5d8572d 100644 |
| 52 | --- a/sysdeps/unix/sysv/linux/powerpc/libc-start.c |
| 53 | +++ b/sysdeps/unix/sysv/linux/powerpc/libc-start.c |
| 54 | @@ -73,11 +73,25 @@ __libc_start_main (int argc, char **argv, |
| 55 | |
| 56 | /* Initialize the __cache_line_size variable from the aux vector. For the |
| 57 | static case, we also need _dl_hwcap, _dl_hwcap2 and _dl_platform, so we |
| 58 | - can call __tcb_parse_hwcap_and_convert_at_platform (). */ |
| 59 | + can call __tcb_parse_hwcap_and_convert_at_platform (). |
| 60 | + |
| 61 | + This is used by memset to optimize setting to zero. We have to |
| 62 | + detect 8xx processors, which have buggy dcbz implementations that |
| 63 | + cannot report page faults correctly. That requires reading SPR, |
| 64 | + which is a privileged operation. Fortunately 2.2.18 and later |
| 65 | + emulates PowerPC mfspr reads from the PVR register. */ |
| 66 | for (ElfW (auxv_t) * av = auxvec; av->a_type != AT_NULL; ++av) |
| 67 | switch (av->a_type) |
| 68 | { |
| 69 | case AT_DCACHEBSIZE: |
| 70 | + if (__LINUX_KERNEL_VERSION >= 0x020218) |
| 71 | + { |
| 72 | + unsigned pvr = 0; |
| 73 | + |
| 74 | + asm ("mfspr %0, 287" : "=r" (pvr) :); |
| 75 | + if ((pvr & 0xffff0000) == 0x00500000) |
| 76 | + break; |
| 77 | + } |
| 78 | __cache_line_size = av->a_un.a_val; |
| 79 | break; |
| 80 | #ifndef SHARED |
| 81 | -- |
| 82 | 2.6.4 |
| 83 | |