[GIT PULL 3.0.x-stable] AMD F15h cache aliasing fixes

[GIT PULL 3.0.x-stable] AMD F15h cache aliasing fixes

[Borislav Petkov]

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Hi Greg,

as previously discussed, here are the 4 patches needed for addressing
the issue in $Subject. I'm sending them as mails but I have them also in
a git-pullable form in case you'd like to verify them:

git://git.kernel.org/pub/scm/linux/kernel/git/bp/bp.git l1i-3.0.x

Here are the patches on the branch above along with SHA1s (from the
bottom up):

bf27c8742db1e2c01bff6e8e2cce3b14d5d6cca5 x86-32, amd: Move va_align definition to unbreak 32-bit build
57d8c29f231049d7b10a497c8afa42dba4672a70 x86, amd: Move BSP code to cpu_dev helper
28b1d99bcde97b468585bdf6c94fa51931d2a1aa x86: Add a BSP cpu_dev helper
5c303905f98ab4e378488c919cc60483d59002ff x86, amd: Avoid cache aliasing penalties on AMD family 15h

Please apply,
thanks.

-- 
Regards/Gruss,
Boris.

Advanced Micro Devices GmbH
Einsteinring 24, 85609 Dornach
GM: Alberto Bozzo
Reg: Dornach, Landkreis Muenchen
HRB Nr. 43632 WEEE Registernr: 129 19551

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[PATCH 1/4] x86, amd: Avoid cache aliasing penalties on AMD family 15h

[Borislav Petkov]

From: Borislav Petkov <borislav.petkov@amd.com>

Upstream commit: dfb09f9b7ab03fd367740e541a5caf830ed56726

This patch provides performance tuning for the "Bulldozer" CPU. With its
shared instruction cache there is a chance of generating an excessive
number of cache cross-invalidates when running specific workloads on the
cores of a compute module.

This excessive amount of cross-invalidations can be observed if cache
lines backed by shared physical memory alias in bits [14:12] of their
virtual addresses, as those bits are used for the index generation.

This patch addresses the issue by clearing all the bits in the [14:12]
slice of the file mapping's virtual address at generation time, thus
forcing those bits the same for all mappings of a single shared library
across processes and, in doing so, avoids instruction cache aliases.

It also adds the command line option "align_va_addr=(32|64|on|off)" with
which virtual address alignment can be enabled for 32-bit or 64-bit x86
individually, or both, or be completely disabled.

This change leaves virtual region address allocation on other families
and/or vendors unaffected.

Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
Link: http://lkml.kernel.org/r/1312550110-24160-2-git-send-email-bp@amd64.org
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
---
 Documentation/kernel-parameters.txt |   13 ++++++
 arch/x86/include/asm/elf.h          |   31 +++++++++++++
 arch/x86/kernel/cpu/amd.c           |   13 ++++++
 arch/x86/kernel/sys_x86_64.c        |   81 +++++++++++++++++++++++++++++++++-
 arch/x86/mm/mmap.c                  |   15 ------
 arch/x86/vdso/vma.c                 |    9 ++++
 6 files changed, 144 insertions(+), 18 deletions(-)

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index aa47be7..af73c03 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -299,6 +299,19 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
 			behaviour to be specified.  Bit 0 enables warnings,
 			bit 1 enables fixups, and bit 2 sends a segfault.
 
+	align_va_addr=	[X86-64]
+			Align virtual addresses by clearing slice [14:12] when
+			allocating a VMA at process creation time. This option
+			gives you up to 3% performance improvement on AMD F15h
+			machines (where it is enabled by default) for a
+			CPU-intensive style benchmark, and it can vary highly in
+			a microbenchmark depending on workload and compiler.
+
+			1: only for 32-bit processes
+			2: only for 64-bit processes
+			on: enable for both 32- and 64-bit processes
+			off: disable for both 32- and 64-bit processes
+
 	amd_iommu=	[HW,X86-84]
 			Pass parameters to the AMD IOMMU driver in the system.
 			Possible values are:
diff --git a/arch/x86/include/asm/elf.h b/arch/x86/include/asm/elf.h
index f2ad216..5f962df 100644
--- a/arch/x86/include/asm/elf.h
+++ b/arch/x86/include/asm/elf.h
@@ -4,6 +4,7 @@
 /*
  * ELF register definitions..
  */
+#include <linux/thread_info.h>
 
 #include <asm/ptrace.h>
 #include <asm/user.h>
@@ -320,4 +321,34 @@ extern int syscall32_setup_pages(struct linux_binprm *, int exstack);
 extern unsigned long arch_randomize_brk(struct mm_struct *mm);
 #define arch_randomize_brk arch_randomize_brk
 
+/*
+ * True on X86_32 or when emulating IA32 on X86_64
+ */
+static inline int mmap_is_ia32(void)
+{
+#ifdef CONFIG_X86_32
+	return 1;
+#endif
+#ifdef CONFIG_IA32_EMULATION
+	if (test_thread_flag(TIF_IA32))
+		return 1;
+#endif
+	return 0;
+}
+
+/* The first two values are special, do not change. See align_addr() */
+enum align_flags {
+	ALIGN_VA_32	= BIT(0),
+	ALIGN_VA_64	= BIT(1),
+	ALIGN_VDSO	= BIT(2),
+	ALIGN_TOPDOWN	= BIT(3),
+};
+
+struct va_alignment {
+	int flags;
+	unsigned long mask;
+} ____cacheline_aligned;
+
+extern struct va_alignment va_align;
+extern unsigned long align_addr(unsigned long, struct file *, enum align_flags);
 #endif /* _ASM_X86_ELF_H */
diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index b13ed39..b0234bc 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -458,6 +458,19 @@ static void __cpuinit early_init_amd(struct cpuinfo_x86 *c)
 					"with P0 frequency!\n");
 		}
 	}
+
+	if (c->x86 == 0x15) {
+		unsigned long upperbit;
+		u32 cpuid, assoc;
+
+		cpuid	 = cpuid_edx(0x80000005);
+		assoc	 = cpuid >> 16 & 0xff;
+		upperbit = ((cpuid >> 24) << 10) / assoc;
+
+		va_align.mask	  = (upperbit - 1) & PAGE_MASK;
+		va_align.flags    = ALIGN_VA_32 | ALIGN_VA_64;
+
+	}
 }
 
 static void __cpuinit init_amd(struct cpuinfo_x86 *c)
diff --git a/arch/x86/kernel/sys_x86_64.c b/arch/x86/kernel/sys_x86_64.c
index ff14a50..aaa8d09 100644
--- a/arch/x86/kernel/sys_x86_64.c
+++ b/arch/x86/kernel/sys_x86_64.c
@@ -18,6 +18,72 @@
 #include <asm/ia32.h>
 #include <asm/syscalls.h>
 
+struct __read_mostly va_alignment va_align = {
+	.flags = -1,
+};
+
+/*
+ * Align a virtual address to avoid aliasing in the I$ on AMD F15h.
+ *
+ * @flags denotes the allocation direction - bottomup or topdown -
+ * or vDSO; see call sites below.
+ */
+unsigned long align_addr(unsigned long addr, struct file *filp,
+			 enum align_flags flags)
+{
+	unsigned long tmp_addr;
+
+	/* handle 32- and 64-bit case with a single conditional */
+	if (va_align.flags < 0 || !(va_align.flags & (2 - mmap_is_ia32())))
+		return addr;
+
+	if (!(current->flags & PF_RANDOMIZE))
+		return addr;
+
+	if (!((flags & ALIGN_VDSO) || filp))
+		return addr;
+
+	tmp_addr = addr;
+
+	/*
+	 * We need an address which is <= than the original
+	 * one only when in topdown direction.
+	 */
+	if (!(flags & ALIGN_TOPDOWN))
+		tmp_addr += va_align.mask;
+
+	tmp_addr &= ~va_align.mask;
+
+	return tmp_addr;
+}
+
+static int __init control_va_addr_alignment(char *str)
+{
+	/* guard against enabling this on other CPU families */
+	if (va_align.flags < 0)
+		return 1;
+
+	if (*str == 0)
+		return 1;
+
+	if (*str == '=')
+		str++;
+
+	if (!strcmp(str, "32"))
+		va_align.flags = ALIGN_VA_32;
+	else if (!strcmp(str, "64"))
+		va_align.flags = ALIGN_VA_64;
+	else if (!strcmp(str, "off"))
+		va_align.flags = 0;
+	else if (!strcmp(str, "on"))
+		va_align.flags = ALIGN_VA_32 | ALIGN_VA_64;
+	else
+		return 0;
+
+	return 1;
+}
+__setup("align_va_addr", control_va_addr_alignment);
+
 SYSCALL_DEFINE6(mmap, unsigned long, addr, unsigned long, len,
 		unsigned long, prot, unsigned long, flags,
 		unsigned long, fd, unsigned long, off)
@@ -92,6 +158,9 @@ arch_get_unmapped_area(struct file *filp, unsigned long addr,
 	start_addr = addr;
 
 full_search:
+
+	addr = align_addr(addr, filp, 0);
+
 	for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
 		/* At this point:  (!vma || addr < vma->vm_end). */
 		if (end - len < addr) {
@@ -117,6 +186,7 @@ full_search:
 			mm->cached_hole_size = vma->vm_start - addr;
 
 		addr = vma->vm_end;
+		addr = align_addr(addr, filp, 0);
 	}
 }
 
@@ -161,10 +231,13 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
 
 	/* make sure it can fit in the remaining address space */
 	if (addr > len) {
-		vma = find_vma(mm, addr-len);
-		if (!vma || addr <= vma->vm_start)
+		unsigned long tmp_addr = align_addr(addr - len, filp,
+						    ALIGN_TOPDOWN);
+
+		vma = find_vma(mm, tmp_addr);
+		if (!vma || tmp_addr + len <= vma->vm_start)
 			/* remember the address as a hint for next time */
-			return mm->free_area_cache = addr-len;
+			return mm->free_area_cache = tmp_addr;
 	}
 
 	if (mm->mmap_base < len)
@@ -173,6 +246,8 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
 	addr = mm->mmap_base-len;
 
 	do {
+		addr = align_addr(addr, filp, ALIGN_TOPDOWN);
+
 		/*
 		 * Lookup failure means no vma is above this address,
 		 * else if new region fits below vma->vm_start,
diff --git a/arch/x86/mm/mmap.c b/arch/x86/mm/mmap.c
index 1dab519..d4c0736 100644
--- a/arch/x86/mm/mmap.c
+++ b/arch/x86/mm/mmap.c
@@ -51,21 +51,6 @@ static unsigned int stack_maxrandom_size(void)
 #define MIN_GAP (128*1024*1024UL + stack_maxrandom_size())
 #define MAX_GAP (TASK_SIZE/6*5)
 
-/*
- * True on X86_32 or when emulating IA32 on X86_64
- */
-static int mmap_is_ia32(void)
-{
-#ifdef CONFIG_X86_32
-	return 1;
-#endif
-#ifdef CONFIG_IA32_EMULATION
-	if (test_thread_flag(TIF_IA32))
-		return 1;
-#endif
-	return 0;
-}
-
 static int mmap_is_legacy(void)
 {
 	if (current->personality & ADDR_COMPAT_LAYOUT)
diff --git a/arch/x86/vdso/vma.c b/arch/x86/vdso/vma.c
index 7abd2be..caa42ce 100644
--- a/arch/x86/vdso/vma.c
+++ b/arch/x86/vdso/vma.c
@@ -69,6 +69,15 @@ static unsigned long vdso_addr(unsigned long start, unsigned len)
 	addr = start + (offset << PAGE_SHIFT);
 	if (addr >= end)
 		addr = end;
+
+	/*
+	 * page-align it here so that get_unmapped_area doesn't
+	 * align it wrongfully again to the next page. addr can come in 4K
+	 * unaligned here as a result of stack start randomization.
+	 */
+	addr = PAGE_ALIGN(addr);
+	addr = align_addr(addr, NULL, ALIGN_VDSO);
+
 	return addr;
 }
 
-- 
1.7.8.rc0

[PATCH 2/4] x86: Add a BSP cpu_dev helper

[Borislav Petkov]

Upstream commit: a110b5ec7371592eac856ac5c22dc7b518952d44

Add a function ptr to struct cpu_dev which is destined to be run only
once on the BSP during boot.

Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
Link: http://lkml.kernel.org/r/20110805180116.GB26217@aftab
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
---
 arch/x86/kernel/cpu/common.c |    3 +++
 arch/x86/kernel/cpu/cpu.h    |    1 +
 2 files changed, 4 insertions(+), 0 deletions(-)

diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 22a073d..8ed394a 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -681,6 +681,9 @@ static void __init early_identify_cpu(struct cpuinfo_x86 *c)
 	filter_cpuid_features(c, false);
 
 	setup_smep(c);
+
+	if (this_cpu->c_bsp_init)
+		this_cpu->c_bsp_init(c);
 }
 
 void __init early_cpu_init(void)
diff --git a/arch/x86/kernel/cpu/cpu.h b/arch/x86/kernel/cpu/cpu.h
index e765633..1b22dcc 100644
--- a/arch/x86/kernel/cpu/cpu.h
+++ b/arch/x86/kernel/cpu/cpu.h
@@ -18,6 +18,7 @@ struct cpu_dev {
 	struct		cpu_model_info c_models[4];
 
 	void            (*c_early_init)(struct cpuinfo_x86 *);
+	void		(*c_bsp_init)(struct cpuinfo_x86 *);
 	void		(*c_init)(struct cpuinfo_x86 *);
 	void		(*c_identify)(struct cpuinfo_x86 *);
 	unsigned int	(*c_size_cache)(struct cpuinfo_x86 *, unsigned int);
-- 
1.7.8.rc0

[PATCH 3/4] x86, amd: Move BSP code to cpu_dev helper

[Borislav Petkov]

Upstream commit: 8fa8b035085e7320c15875c1f6b03b290ca2dd66

Move code which is run once on the BSP during boot into the cpu_dev
helper.

[ hpa: removed bogus cpu_has -> static_cpu_has conversion ]

Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
Link: http://lkml.kernel.org/r/20110805180409.GC26217@aftab
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
---
 arch/x86/kernel/cpu/amd.c |   59 ++++++++++++++++++++++-----------------------
 1 files changed, 29 insertions(+), 30 deletions(-)

diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index b0234bc..b6e3e87 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -410,6 +410,34 @@ static void __cpuinit early_init_amd_mc(struct cpuinfo_x86 *c)
 #endif
 }
 
+static void __cpuinit bsp_init_amd(struct cpuinfo_x86 *c)
+{
+	if (cpu_has(c, X86_FEATURE_CONSTANT_TSC)) {
+
+		if (c->x86 > 0x10 ||
+		    (c->x86 == 0x10 && c->x86_model >= 0x2)) {
+			u64 val;
+
+			rdmsrl(MSR_K7_HWCR, val);
+			if (!(val & BIT(24)))
+				printk(KERN_WARNING FW_BUG "TSC doesn't count "
+					"with P0 frequency!\n");
+		}
+	}
+
+	if (c->x86 == 0x15) {
+		unsigned long upperbit;
+		u32 cpuid, assoc;
+
+		cpuid	 = cpuid_edx(0x80000005);
+		assoc	 = cpuid >> 16 & 0xff;
+		upperbit = ((cpuid >> 24) << 10) / assoc;
+
+		va_align.mask	  = (upperbit - 1) & PAGE_MASK;
+		va_align.flags    = ALIGN_VA_32 | ALIGN_VA_64;
+	}
+}
+
 static void __cpuinit early_init_amd(struct cpuinfo_x86 *c)
 {
 	early_init_amd_mc(c);
@@ -441,36 +469,6 @@ static void __cpuinit early_init_amd(struct cpuinfo_x86 *c)
 			set_cpu_cap(c, X86_FEATURE_EXTD_APICID);
 	}
 #endif
-
-	/* We need to do the following only once */
-	if (c != &boot_cpu_data)
-		return;
-
-	if (cpu_has(c, X86_FEATURE_CONSTANT_TSC)) {
-
-		if (c->x86 > 0x10 ||
-		    (c->x86 == 0x10 && c->x86_model >= 0x2)) {
-			u64 val;
-
-			rdmsrl(MSR_K7_HWCR, val);
-			if (!(val & BIT(24)))
-				printk(KERN_WARNING FW_BUG "TSC doesn't count "
-					"with P0 frequency!\n");
-		}
-	}
-
-	if (c->x86 == 0x15) {
-		unsigned long upperbit;
-		u32 cpuid, assoc;
-
-		cpuid	 = cpuid_edx(0x80000005);
-		assoc	 = cpuid >> 16 & 0xff;
-		upperbit = ((cpuid >> 24) << 10) / assoc;
-
-		va_align.mask	  = (upperbit - 1) & PAGE_MASK;
-		va_align.flags    = ALIGN_VA_32 | ALIGN_VA_64;
-
-	}
 }
 
 static void __cpuinit init_amd(struct cpuinfo_x86 *c)
@@ -692,6 +690,7 @@ static const struct cpu_dev __cpuinitconst amd_cpu_dev = {
 	.c_size_cache	= amd_size_cache,
 #endif
 	.c_early_init   = early_init_amd,
+	.c_bsp_init	= bsp_init_amd,
 	.c_init		= init_amd,
 	.c_x86_vendor	= X86_VENDOR_AMD,
 };
-- 
1.7.8.rc0

[PATCH 4/4] x86-32, amd: Move va_align definition to unbreak 32-bit build

[Borislav Petkov]

From: Borislav Petkov <borislav.petkov@amd.com>

Upstream commit: 9387f774d61b01ab71bade85e6d0bfab0b3419bd

hpa reported that dfb09f9b7ab03fd367740e541a5caf830ed56726 breaks 32-bit
builds with the following error message:

/home/hpa/kernel/linux-tip.cpu/arch/x86/kernel/cpu/amd.c:437: undefined
reference to `va_align'
/home/hpa/kernel/linux-tip.cpu/arch/x86/kernel/cpu/amd.c:436: undefined
reference to `va_align'

This is due to the fact that va_align is a global in a 64-bit only
compilation unit. Move it to mmap.c where it is visible to both
subarches.

Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
Link: http://lkml.kernel.org/r/1312633899-1131-1-git-send-email-bp@amd64.org
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
---
 arch/x86/kernel/sys_x86_64.c |    4 ----
 arch/x86/mm/mmap.c           |    5 ++++-
 2 files changed, 4 insertions(+), 5 deletions(-)

diff --git a/arch/x86/kernel/sys_x86_64.c b/arch/x86/kernel/sys_x86_64.c
index aaa8d09..fe7d2da 100644
--- a/arch/x86/kernel/sys_x86_64.c
+++ b/arch/x86/kernel/sys_x86_64.c
@@ -18,10 +18,6 @@
 #include <asm/ia32.h>
 #include <asm/syscalls.h>
 
-struct __read_mostly va_alignment va_align = {
-	.flags = -1,
-};
-
 /*
  * Align a virtual address to avoid aliasing in the I$ on AMD F15h.
  *
diff --git a/arch/x86/mm/mmap.c b/arch/x86/mm/mmap.c
index d4c0736..4b5ba85 100644
--- a/arch/x86/mm/mmap.c
+++ b/arch/x86/mm/mmap.c
@@ -31,6 +31,10 @@
 #include <linux/sched.h>
 #include <asm/elf.h>
 
+struct __read_mostly va_alignment va_align = {
+	.flags = -1,
+};
+
 static unsigned int stack_maxrandom_size(void)
 {
 	unsigned int max = 0;
@@ -42,7 +46,6 @@ static unsigned int stack_maxrandom_size(void)
 	return max;
 }
 
-
 /*
  * Top of mmap area (just below the process stack).
  *
-- 
1.7.8.rc0