From: Bhavna Sarathy <bnagendr@redhat.com>
Date: Wed, 21 Oct 2009 20:18:46 -0400
Subject: [x86] amd: fix hot plug cpu issue on 32-bit magny-cours
Message-id: <20091021202107.22207.17474.sendpatchset@localhost.localdomain>
Patchwork-id: 21151
O-Subject: [RHEL5.5 PATCH 1/2] Fix hot plug CPU issue on 32-bit AMD M-C
Bugzilla: 526770
RH-Acked-by: Christopher Lalancette <clalance@redhat.com>

Resolves BZ 526770

This patch fixes a hot plug issue on AMD processors on 32-bit RHEL.
The init_amd() functions belong in the wrong code section.
It's in __init and this section is removed during boot. Now if the kernel
tries to call this function during CPU hotplug the function pointer is
invalid.

Testing:
Tested on a few AMD Magny-cours systems, and it fixes the crash on the
5.4 experimental kernel.

Upstream:
This is a RHEL specific issue and does not exist upstream, upstream has
unified 32-bit and 64-bit code.

Please review and ACK

diff --git a/arch/i386/kernel/cpu/amd.c b/arch/i386/kernel/cpu/amd.c
index 5564d53..58f5e41 100644
--- a/arch/i386/kernel/cpu/amd.c
+++ b/arch/i386/kernel/cpu/amd.c
@@ -23,7 +23,7 @@
 extern void vide(void);
 __asm__(".align 4\nvide: ret");
 
-int force_mwait __initdata;
+int force_mwait __cpuinitdata;
 
 /*
  * Fixup core topology information for AMD multi-node processors.
@@ -83,7 +83,7 @@ static void __cpuinit amd_fixup_dcm(struct cpuinfo_x86 *c)
 }
 #endif
 
-static void __init init_amd(struct cpuinfo_x86 *c)
+static void __cpuinit init_amd(struct cpuinfo_x86 *c)
 {
 	u32 l, h;
 	int mbytes = num_physpages >> (20-PAGE_SHIFT);
@@ -321,7 +321,7 @@ static void __init init_amd(struct cpuinfo_x86 *c)
 		clear_bit(X86_FEATURE_MWAIT, &c->x86_capability);
 }
 
-static unsigned int amd_size_cache(struct cpuinfo_x86 * c, unsigned int size)
+static unsigned int __cpuinit amd_size_cache(struct cpuinfo_x86 * c, unsigned int size)
 {
 	/* AMD errata T13 (order #21922) */
 	if ((c->x86 == 6)) {
@@ -334,7 +334,7 @@ static unsigned int amd_size_cache(struct cpuinfo_x86 * c, unsigned int size)
 	return size;
 }
 
-static struct cpu_dev amd_cpu_dev __initdata = {
+static struct cpu_dev amd_cpu_dev __cpuinitdata = {
 	.c_vendor	= "AMD",
 	.c_ident 	= { "AuthenticAMD" },
 	.c_models = {
@@ -362,10 +362,3 @@ int __init amd_init_cpu(void)
 
 //early_arch_initcall(amd_init_cpu);
 
-static int __init amd_exit_cpu(void)
-{
-	cpu_devs[X86_VENDOR_AMD] = NULL;
-	return 0;
-}
-
-late_initcall(amd_exit_cpu);