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authorBenjamin Herrenschmidt <benh@kernel.crashing.org>2005-04-16 15:24:36 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:24:36 -0700
commit187335a4ec72c9bc7f3f168d6858a41fcfb63302 (patch)
treed5f1ae0d320e6325ed056469773e855fc635c53d /arch
parent547ee84cea37696d25c93306e909378a87db2f66 (diff)
downloadop-kernel-dev-187335a4ec72c9bc7f3f168d6858a41fcfb63302.zip
op-kernel-dev-187335a4ec72c9bc7f3f168d6858a41fcfb63302.tar.gz
[PATCH] ppc64: Detect altivec via firmware on unknown CPUs
This patch adds detection of the Altivec capability of the CPU via the firmware in addition to the cpu table. This allows newer CPUs that aren't in the table to still have working altivec support in the kernel. It also fixes a problem where if a CPU isn't recognized as having altivec features, and takes an altivec unavailable exception due to userland issuing altivec instructions, the kernel would happily enable it and context switch the registers ... but not all of them (it would basically forget vrsave). With this patch, the kernel will refuse to enable altivec when the feature isn't detected for the CPU (SIGILL). Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/ppc64/kernel/head.S2
-rw-r--r--arch/ppc64/kernel/prom.c19
-rw-r--r--arch/ppc64/kernel/traps.c2
3 files changed, 20 insertions, 3 deletions
diff --git a/arch/ppc64/kernel/head.S b/arch/ppc64/kernel/head.S
index fe05f3f..92a744c 100644
--- a/arch/ppc64/kernel/head.S
+++ b/arch/ppc64/kernel/head.S
@@ -922,7 +922,9 @@ fp_unavailable_common:
altivec_unavailable_common:
EXCEPTION_PROLOG_COMMON(0xf20, PACA_EXGEN)
#ifdef CONFIG_ALTIVEC
+BEGIN_FTR_SECTION
bne .load_up_altivec /* if from user, just load it up */
+END_FTR_SECTION_IFSET(CPU_FTR_ALTIVEC)
#endif
bl .save_nvgprs
addi r3,r1,STACK_FRAME_OVERHEAD
diff --git a/arch/ppc64/kernel/prom.c b/arch/ppc64/kernel/prom.c
index 01739d5..b08aac6 100644
--- a/arch/ppc64/kernel/prom.c
+++ b/arch/ppc64/kernel/prom.c
@@ -885,6 +885,7 @@ static int __init early_init_dt_scan_cpus(unsigned long node,
const char *full_path, void *data)
{
char *type = get_flat_dt_prop(node, "device_type", NULL);
+ u32 *prop;
/* We are scanning "cpu" nodes only */
if (type == NULL || strcmp(type, "cpu") != 0)
@@ -916,6 +917,20 @@ static int __init early_init_dt_scan_cpus(unsigned long node,
}
}
+ /* Check if we have a VMX and eventually update CPU features */
+ prop = (u32 *)get_flat_dt_prop(node, "ibm,vmx", NULL);
+ if (prop && (*prop) > 0) {
+ cur_cpu_spec->cpu_features |= CPU_FTR_ALTIVEC;
+ cur_cpu_spec->cpu_user_features |= PPC_FEATURE_HAS_ALTIVEC;
+ }
+
+ /* Same goes for Apple's "altivec" property */
+ prop = (u32 *)get_flat_dt_prop(node, "altivec", NULL);
+ if (prop) {
+ cur_cpu_spec->cpu_features |= CPU_FTR_ALTIVEC;
+ cur_cpu_spec->cpu_user_features |= PPC_FEATURE_HAS_ALTIVEC;
+ }
+
return 0;
}
@@ -1104,7 +1119,9 @@ void __init early_init_devtree(void *params)
DBG("Scanning CPUs ...\n");
- /* Retreive hash table size from flattened tree */
+ /* Retreive hash table size from flattened tree plus other
+ * CPU related informations (altivec support, boot CPU ID, ...)
+ */
scan_flat_dt(early_init_dt_scan_cpus, NULL);
/* If hash size wasn't obtained above, we calculate it now based on
diff --git a/arch/ppc64/kernel/traps.c b/arch/ppc64/kernel/traps.c
index 10fc61f..7e52cb2 100644
--- a/arch/ppc64/kernel/traps.c
+++ b/arch/ppc64/kernel/traps.c
@@ -450,14 +450,12 @@ void kernel_fp_unavailable_exception(struct pt_regs *regs)
void altivec_unavailable_exception(struct pt_regs *regs)
{
-#ifndef CONFIG_ALTIVEC
if (user_mode(regs)) {
/* A user program has executed an altivec instruction,
but this kernel doesn't support altivec. */
_exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
return;
}
-#endif
printk(KERN_EMERG "Unrecoverable VMX/Altivec Unavailable Exception "
"%lx at %lx\n", regs->trap, regs->nip);
die("Unrecoverable VMX/Altivec Unavailable Exception", regs, SIGABRT);
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