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 <[email protected]>
---
Note: I wasn't sure how to pick the index value for AT_BASE_PLATFORM;
I simply searched include/ for all AT_ values and added 1 to the
highest value found.
arch/powerpc/kernel/cputable.c | 11 +++++++++++
include/asm-powerpc/auxvec.h | 3 +++
include/asm-powerpc/cputable.h | 2 ++
include/asm-powerpc/elf.h | 8 ++++++++
4 files changed, 24 insertions(+), 0 deletions(-)
diff --git a/arch/powerpc/kernel/cputable.c b/arch/powerpc/kernel/cputable.c
index a9c90be..f1eb632 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
@@ -1620,6 +1623,14 @@ 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/auxvec.h b/include/asm-powerpc/auxvec.h
index 19a099b..507f081 100644
--- a/include/asm-powerpc/auxvec.h
+++ b/include/asm-powerpc/auxvec.h
@@ -16,4 +16,7 @@
*/
#define AT_SYSINFO_EHDR 33
+/* The actual hardware platform; may differ from AT_PLATFORM */
+#define AT_BASE_PLATFORM 38
+
#endif
diff --git a/include/asm-powerpc/cputable.h b/include/asm-powerpc/cputable.h
index a9c1de3..527152f 100644
--- a/include/asm-powerpc/cputable.h
+++ b/include/asm-powerpc/cputable.h
@@ -125,6 +125,8 @@ 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 38a5172..ff0c947 100644
--- a/include/asm-powerpc/elf.h
+++ b/include/asm-powerpc/elf.h
@@ -237,6 +237,14 @@ extern int dump_task_altivec(struct task_struct *, elf_vrregset_t *vrregs);
#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; \
--
1.5.5.1