[PATCH] enable AT_BASE_PLATFORM aux vector for powerpc

Nathan Lynch
2008-07-15T23:59:42Z

Stash the first platform string matched by identify_cpu() in
powerpc_base_platform, and supply that to the ELF loader for the value
of AT_BASE_PLATFORM.

Signed-off-by: Nathan Lynch <ntl@pobox.com>
---
arch/powerpc/kernel/cputable.c | 11 +++++++++++
include/asm-powerpc/cputable.h | 2 ++
include/asm-powerpc/elf.h | 8 ++++++++
3 files changed, 21 insertions(+), 0 deletions(-)

diff --git a/arch/powerpc/kernel/cputable.c b/arch/powerpc/kernel/cputable.c
index f7f3c21..89d8731 100644
--- a/arch/powerpc/kernel/cputable.c
+++ b/arch/powerpc/kernel/cputable.c
@@ -23,6 +23,9 @@
struct cpu_spec* cur_cpu_spec = NULL;
EXPORT_SYMBOL(cur_cpu_spec);

+/* The platform string corresponding to the real PVR */
+const char *powerpc_base_platform;
+
/* NOTE:
* Unlike ppc32, ppc64 will only call this once for the boot CPU, it's
* the responsibility of the appropriate CPU save/restore functions to
@@ -1632,6 +1635,14 @@ struct cpu_spec * __init identify_cpu(unsigned long offset, unsigned int pvr)
} else
*t = *s;
*PTRRELOC(&cur_cpu_spec) = &the_cpu_spec;
+
+ /*
+ * Set the base platform string once; assumes
+ * we're called with real pvr first.
+ */
+ if (powerpc_base_platform == NULL)
+ powerpc_base_platform = t->platform;
+
#if defined(CONFIG_PPC64) || defined(CONFIG_BOOKE)
/* ppc64 and booke expect identify_cpu to also call
* setup_cpu for that processor. I will consolidate
diff --git a/include/asm-powerpc/cputable.h b/include/asm-powerpc/cputable.h
index 2a3e907..ef8a248 100644
--- a/include/asm-powerpc/cputable.h
+++ b/include/asm-powerpc/cputable.h
@@ -127,6 +127,8 @@ extern struct cpu_spec *identify_cpu(unsigned long offset, unsigned int pvr);
extern void do_feature_fixups(unsigned long value, void *fixup_start,
void *fixup_end);

+extern const char *powerpc_base_platform;
+
#endif /* __ASSEMBLY__ */

/* CPU kernel features */
diff --git a/include/asm-powerpc/elf.h b/include/asm-powerpc/elf.h
index 8966467..80d1f39 100644
--- a/include/asm-powerpc/elf.h
+++ b/include/asm-powerpc/elf.h
@@ -217,6 +217,14 @@ typedef elf_vrregset_t elf_fpxregset_t;

#define ELF_PLATFORM (cur_cpu_spec->platform)

+/* While ELF_PLATFORM indicates the ISA supported by the platform, it
+ * may not accurately reflect the underlying behavior of the hardware
+ * (as in the case of running in Power5+ compatibility mode on a
+ * Power6 machine). ELF_BASE_PLATFORM allows ld.so to load libraries
+ * that are tuned for the real hardware.
+ */
+#define ELF_BASE_PLATFORM (powerpc_base_platform)
+
#ifdef __powerpc64__
# define ELF_PLAT_INIT(_r, load_addr) do { \
_r->gpr[2] = load_addr; \
--
1.5.6.2