[PATCH 1/5] Fix xen_cpuid() inline asm to not clobber stack's red zone

[PATCH 1/5] Fix xen_cpuid() inline asm to not clobber stack's red zone

[Olaf Hering]

Port xen-unstable changeset 24344:72f4e4cb7440 to kexec-tools:

  Pushing stuff onto the stack on x86-64 when we do not specify
  -mno-red-zone is unsafe. Since the complicated asm is due to register
  pressure on i386, we simply implement an all-new simpler alternative
  for x86-64.

Signed-off-by: Olaf Hering <olaf@aepfle.de>
---
 kexec/crashdump-xen.c | 21 ++++++++++++---------
 1 file changed, 12 insertions(+), 9 deletions(-)

diff --git a/kexec/crashdump-xen.c b/kexec/crashdump-xen.c
index 9dfabf8..d8bd0f4 100644
--- a/kexec/crashdump-xen.c
+++ b/kexec/crashdump-xen.c
@@ -41,18 +41,21 @@ void xen_sigill_handler(int sig)
 
 static void xen_cpuid(uint32_t idx, uint32_t *regs, int pv_context)
 {
-	asm volatile (
 #ifdef __i386__
-#define R(x) "%%e"#x"x"
+    /* Use the stack to avoid reg constraint failures with some gcc flags */
+    asm volatile (
+        "push %%eax; push %%ebx; push %%ecx; push %%edx\n\t"
+        "test %1,%1 ; jz 1f ; ud2a ; .ascii \"xen\" ; 1: cpuid\n\t"
+        "mov %%eax,(%2); mov %%ebx,4(%2)\n\t"
+        "mov %%ecx,8(%2); mov %%edx,12(%2)\n\t"
+        "pop %%edx; pop %%ecx; pop %%ebx; pop %%eax\n\t"
+        : : "a" (idx), "c" (pv_context), "S" (regs) : "memory" );
 #else
-#define R(x) "%%r"#x"x"
+    asm volatile (
+        "test %5,%5 ; jz 1f ; ud2a ; .ascii \"xen\" ; 1: cpuid\n\t"
+        : "=a" (regs[0]), "=b" (regs[1]), "=c" (regs[2]), "=d" (regs[3])
+        : "0" (idx), "1" (pv_context), "2" (0) );
 #endif
-	"push "R(a)"; push "R(b)"; push "R(c)"; push "R(d)"\n\t"
-	"test %1,%1 ; jz 1f ; ud2a ; .ascii \"xen\" ; 1: cpuid\n\t"
-	"mov %%eax,(%2); mov %%ebx,4(%2)\n\t"
-	"mov %%ecx,8(%2); mov %%edx,12(%2)\n\t"
-	"pop "R(d)"; pop "R(c)"; pop "R(b)"; pop "R(a)"\n\t"
-	: : "a" (idx), "c" (pv_context), "S" (regs) : "memory" );
 }
 
 static int check_for_xen(int pv_context)
-- 
1.8.0.1


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[PATCH 2/5] fixed strncat size argument on ppc64

[Olaf Hering]

Signed-off-by: Olaf Hering <olaf@aepfle.de>
---
 kexec/arch/ppc64/fs2dt.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/kexec/arch/ppc64/fs2dt.c b/kexec/arch/ppc64/fs2dt.c
index d2b6b18..f02540d 100644
--- a/kexec/arch/ppc64/fs2dt.c
+++ b/kexec/arch/ppc64/fs2dt.c
@@ -499,7 +499,7 @@ static void putnode(void)
 
 	basename = strrchr(pathname,'/');
 
-	strcat(pathname, "/");
+	strncat(pathname, "/", MAXPATH - strlen(pathname) - 1);
 	dn = pathname + strlen(pathname);
 
 	putprops(dn, namelist, numlist);
@@ -560,7 +560,7 @@ static void putnode(void)
 			char *old_param;
 
 			strcpy(filename, pathname);
-			strcat(filename, "bootargs");
+			strncat(filename, "bootargs", MAXPATH - strlen(filename) - 1);
 			fp = fopen(filename, "r");
 			if (fp) {
 				if (getline(&last_cmdline, &cmd_len, fp) == -1)
@@ -599,7 +599,7 @@ static void putnode(void)
 		 * pseries/hvcterminal is supported.
 		 */
 		strcpy(filename, pathname);
-		strncat(filename, "linux,stdout-path", MAXPATH);
+		strncat(filename, "linux,stdout-path", MAXPATH - strlen(filename) - 1);
 		fd = open(filename, O_RDONLY);
 		if (fd == -1) {
 			printf("Unable to find %s, printing from purgatory is diabled\n",
@@ -623,8 +623,8 @@ static void putnode(void)
 		read(fd, buff, statbuf.st_size);
 		close(fd);
 		strncpy(filename, "/proc/device-tree/", MAXPATH);
-		strncat(filename, buff, MAXPATH);
-		strncat(filename, "/compatible", MAXPATH);
+		strncat(filename, buff, MAXPATH - strlen(filename) - 1);
+		strncat(filename, "/compatible", MAXPATH - strlen(filename) - 1);
 		fd = open(filename, O_RDONLY);
 		if (fd == -1) {
 			printf("Unable to find %s printing from purgatory is diabled\n",
-- 
1.8.0.1


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[PATCH 3/5] fix message and indenting in putnode in ppc64

[Olaf Hering]

Signed-off-by: Olaf Hering <olaf@aepfle.de>
---
 kexec/arch/ppc64/fs2dt.c | 12 ++++--------
 1 file changed, 4 insertions(+), 8 deletions(-)

diff --git a/kexec/arch/ppc64/fs2dt.c b/kexec/arch/ppc64/fs2dt.c
index f02540d..9750c34 100644
--- a/kexec/arch/ppc64/fs2dt.c
+++ b/kexec/arch/ppc64/fs2dt.c
@@ -602,13 +602,11 @@ static void putnode(void)
 		strncat(filename, "linux,stdout-path", MAXPATH - strlen(filename) - 1);
 		fd = open(filename, O_RDONLY);
 		if (fd == -1) {
-			printf("Unable to find %s, printing from purgatory is diabled\n",
-														filename);
+			printf("Unable to find %s, printing from purgatory is disabled\n", filename);
 			goto no_debug;
 		}
 		if (fstat(fd, &statbuf)) {
-			printf("Unable to stat %s, printing from purgatory is diabled\n",
-														filename);
+			printf("Unable to stat %s, printing from purgatory is disabled\n", filename);
 			close(fd);
 			goto no_debug;
 
@@ -627,13 +625,11 @@ static void putnode(void)
 		strncat(filename, "/compatible", MAXPATH - strlen(filename) - 1);
 		fd = open(filename, O_RDONLY);
 		if (fd == -1) {
-			printf("Unable to find %s printing from purgatory is diabled\n",
-														filename);
+			printf("Unable to find %s printing from purgatory is disabled\n", filename);
 			goto no_debug;
 		}
 		if (fstat(fd, &statbuf)) {
-			printf("Unable to stat %s printing from purgatory is diabled\n",
-														filename);
+			printf("Unable to stat %s printing from purgatory is disabled\n", filename);
 			close(fd);
 			goto no_debug;
 		}
-- 
1.8.0.1


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[PATCH 4/5] fix comment typo in do_bzImage_load on x86

[Olaf Hering]

Signed-off-by: Olaf Hering <olaf@aepfle.de>
---
 kexec/arch/i386/kexec-bzImage.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kexec/arch/i386/kexec-bzImage.c b/kexec/arch/i386/kexec-bzImage.c
index 6998587..fd214a3 100644
--- a/kexec/arch/i386/kexec-bzImage.c
+++ b/kexec/arch/i386/kexec-bzImage.c
@@ -194,7 +194,7 @@ int do_bzImage_load(struct kexec_info *info,
 	}
 
 	/* Load the trampoline.  This must load at a higher address
-	 * the the argument/parameter segment or the kernel will stomp
+	 * than the argument/parameter segment or the kernel will stomp
 	 * it's gdt.
 	 *
 	 * x86_64 purgatory code has got relocations type R_X86_64_32S
-- 
1.8.0.1


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[PATCH 5/5] fix comment typo in locate_hole

[Olaf Hering]

Signed-off-by: Olaf Hering <olaf@aepfle.de>
---
 kexec/kexec.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kexec/kexec.c b/kexec/kexec.c
index 8928be0..22229d8 100644
--- a/kexec/kexec.c
+++ b/kexec/kexec.c
@@ -202,7 +202,7 @@ unsigned long locate_hole(struct kexec_info *info,
 		die("Invalid hole end argument of 0 specified to locate_hole");
 	}
 
-	/* Set an intial invalid value for the hole base */
+	/* Set an initial invalid value for the hole base */
 	hole_base = ULONG_MAX;
 
 	/* Align everything to at least a page size boundary */
-- 
1.8.0.1


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Re: [PATCH 1/5] Fix xen_cpuid() inline asm to not clobber stack's red zone

[Simon Horman]

On Thu, Dec 13, 2012 at 04:48:46PM +0100, Olaf Hering wrote:
> Port xen-unstable changeset 24344:72f4e4cb7440 to kexec-tools:
> 
>   Pushing stuff onto the stack on x86-64 when we do not specify
>   -mno-red-zone is unsafe. Since the complicated asm is due to register
>   pressure on i386, we simply implement an all-new simpler alternative
>   for x86-64.

Thanks, all 5 patches applied.

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