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authorThomas Gleixner <tglx@linutronix.de>2017-03-10 07:17:18 -0500
committerThomas Gleixner <tglx@linutronix.de>2017-03-10 14:55:09 -0500
commit40c50c1fecdf012a3bf055ec813f0ef2eda2749c (patch)
treeff3b781d968411004fada1618550b4a9dd55136a
parentbba8376aea1dcbbe22bbda118c52abee317c7609 (diff)
kexec, x86/purgatory: Unbreak it and clean it up
The purgatory code defines global variables which are referenced via a symbol lookup in the kexec code (core and arch). A recent commit addressing sparse warnings made these static and thereby broke kexec_file. Why did this happen? Simply because the whole machinery is undocumented and lacks any form of forward declarations. The variable names are unspecific and lack a prefix, so adding forward declarations creates shadow variables in the core code. Aside of that the code relies on magic constants and duplicate struct definitions with no way to ensure that these things stay in sync. The section placement of the purgatory variables happened by chance and not by design. Unbreak kexec and cleanup the mess: - Add proper forward declarations and document the usage - Use common struct definition - Use the proper common defines instead of magic constants - Add a purgatory_ prefix to have a proper name space - Use ARRAY_SIZE() instead of a homebrewn reimplementation - Add proper sections to the purgatory variables [ From Mike ] Fixes: 72042a8c7b01 ("x86/purgatory: Make functions and variables static") Reported-by: Mike Galbraith <<efault@gmx.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Nicholas Mc Guire <der.herr@hofr.at> Cc: Borislav Petkov <bp@alien8.de> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: "Tobin C. Harding" <me@tobin.cc> Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1703101315140.3681@nanos Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
-rw-r--r--arch/powerpc/purgatory/trampoline.S12
-rw-r--r--arch/x86/include/asm/purgatory.h20
-rw-r--r--arch/x86/kernel/machine_kexec_64.c9
-rw-r--r--arch/x86/purgatory/purgatory.c35
-rw-r--r--arch/x86/purgatory/purgatory.h8
-rw-r--r--arch/x86/purgatory/setup-x86_64.S2
-rw-r--r--arch/x86/purgatory/sha256.h1
-rw-r--r--include/linux/purgatory.h23
-rw-r--r--kernel/kexec_file.c8
-rw-r--r--kernel/kexec_internal.h6
10 files changed, 78 insertions, 46 deletions
diff --git a/arch/powerpc/purgatory/trampoline.S b/arch/powerpc/purgatory/trampoline.S
index f9760ccf4032..3696ea6c4826 100644
--- a/arch/powerpc/purgatory/trampoline.S
+++ b/arch/powerpc/purgatory/trampoline.S
@@ -116,13 +116,13 @@ dt_offset:
116 116
117 .data 117 .data
118 .balign 8 118 .balign 8
119.globl sha256_digest 119.globl purgatory_sha256_digest
120sha256_digest: 120purgatory_sha256_digest:
121 .skip 32 121 .skip 32
122 .size sha256_digest, . - sha256_digest 122 .size purgatory_sha256_digest, . - purgatory_sha256_digest
123 123
124 .balign 8 124 .balign 8
125.globl sha_regions 125.globl purgatory_sha_regions
126sha_regions: 126purgatory_sha_regions:
127 .skip 8 * 2 * 16 127 .skip 8 * 2 * 16
128 .size sha_regions, . - sha_regions 128 .size purgatory_sha_regions, . - purgatory_sha_regions
diff --git a/arch/x86/include/asm/purgatory.h b/arch/x86/include/asm/purgatory.h
new file mode 100644
index 000000000000..d7da2729903d
--- /dev/null
+++ b/arch/x86/include/asm/purgatory.h
@@ -0,0 +1,20 @@
1#ifndef _ASM_X86_PURGATORY_H
2#define _ASM_X86_PURGATORY_H
3
4#ifndef __ASSEMBLY__
5#include <linux/purgatory.h>
6
7extern void purgatory(void);
8/*
9 * These forward declarations serve two purposes:
10 *
11 * 1) Make sparse happy when checking arch/purgatory
12 * 2) Document that these are required to be global so the symbol
13 * lookup in kexec works
14 */
15extern unsigned long purgatory_backup_dest;
16extern unsigned long purgatory_backup_src;
17extern unsigned long purgatory_backup_sz;
18#endif /* __ASSEMBLY__ */
19
20#endif /* _ASM_PURGATORY_H */
diff --git a/arch/x86/kernel/machine_kexec_64.c b/arch/x86/kernel/machine_kexec_64.c
index 307b1f4543de..857cdbd02867 100644
--- a/arch/x86/kernel/machine_kexec_64.c
+++ b/arch/x86/kernel/machine_kexec_64.c
@@ -194,19 +194,22 @@ static int arch_update_purgatory(struct kimage *image)
194 194
195 /* Setup copying of backup region */ 195 /* Setup copying of backup region */
196 if (image->type == KEXEC_TYPE_CRASH) { 196 if (image->type == KEXEC_TYPE_CRASH) {
197 ret = kexec_purgatory_get_set_symbol(image, "backup_dest", 197 ret = kexec_purgatory_get_set_symbol(image,
198 "purgatory_backup_dest",
198 &image->arch.backup_load_addr, 199 &image->arch.backup_load_addr,
199 sizeof(image->arch.backup_load_addr), 0); 200 sizeof(image->arch.backup_load_addr), 0);
200 if (ret) 201 if (ret)
201 return ret; 202 return ret;
202 203
203 ret = kexec_purgatory_get_set_symbol(image, "backup_src", 204 ret = kexec_purgatory_get_set_symbol(image,
205 "purgatory_backup_src",
204 &image->arch.backup_src_start, 206 &image->arch.backup_src_start,
205 sizeof(image->arch.backup_src_start), 0); 207 sizeof(image->arch.backup_src_start), 0);
206 if (ret) 208 if (ret)
207 return ret; 209 return ret;
208 210
209 ret = kexec_purgatory_get_set_symbol(image, "backup_sz", 211 ret = kexec_purgatory_get_set_symbol(image,
212 "purgatory_backup_sz",
210 &image->arch.backup_src_sz, 213 &image->arch.backup_src_sz,
211 sizeof(image->arch.backup_src_sz), 0); 214 sizeof(image->arch.backup_src_sz), 0);
212 if (ret) 215 if (ret)
diff --git a/arch/x86/purgatory/purgatory.c b/arch/x86/purgatory/purgatory.c
index b6d5c8946e66..470edad96bb9 100644
--- a/arch/x86/purgatory/purgatory.c
+++ b/arch/x86/purgatory/purgatory.c
@@ -10,22 +10,19 @@
10 * Version 2. See the file COPYING for more details. 10 * Version 2. See the file COPYING for more details.
11 */ 11 */
12 12
13#include <linux/bug.h>
14#include <asm/purgatory.h>
15
13#include "sha256.h" 16#include "sha256.h"
14#include "purgatory.h"
15#include "../boot/string.h" 17#include "../boot/string.h"
16 18
17struct sha_region { 19unsigned long purgatory_backup_dest __section(.kexec-purgatory);
18 unsigned long start; 20unsigned long purgatory_backup_src __section(.kexec-purgatory);
19 unsigned long len; 21unsigned long purgatory_backup_sz __section(.kexec-purgatory);
20};
21
22static unsigned long backup_dest;
23static unsigned long backup_src;
24static unsigned long backup_sz;
25 22
26static u8 sha256_digest[SHA256_DIGEST_SIZE] = { 0 }; 23u8 purgatory_sha256_digest[SHA256_DIGEST_SIZE] __section(.kexec-purgatory);
27 24
28struct sha_region sha_regions[16] = {}; 25struct kexec_sha_region purgatory_sha_regions[KEXEC_SEGMENT_MAX] __section(.kexec-purgatory);
29 26
30/* 27/*
31 * On x86, second kernel requries first 640K of memory to boot. Copy 28 * On x86, second kernel requries first 640K of memory to boot. Copy
@@ -34,26 +31,28 @@ struct sha_region sha_regions[16] = {};
34 */ 31 */
35static int copy_backup_region(void) 32static int copy_backup_region(void)
36{ 33{
37 if (backup_dest) 34 if (purgatory_backup_dest) {
38 memcpy((void *)backup_dest, (void *)backup_src, backup_sz); 35 memcpy((void *)purgatory_backup_dest,
39 36 (void *)purgatory_backup_src, purgatory_backup_sz);
37 }
40 return 0; 38 return 0;
41} 39}
42 40
43static int verify_sha256_digest(void) 41static int verify_sha256_digest(void)
44{ 42{
45 struct sha_region *ptr, *end; 43 struct kexec_sha_region *ptr, *end;
46 u8 digest[SHA256_DIGEST_SIZE]; 44 u8 digest[SHA256_DIGEST_SIZE];
47 struct sha256_state sctx; 45 struct sha256_state sctx;
48 46
49 sha256_init(&sctx); 47 sha256_init(&sctx);
50 end = &sha_regions[sizeof(sha_regions)/sizeof(sha_regions[0])]; 48 end = purgatory_sha_regions + ARRAY_SIZE(purgatory_sha_regions);
51 for (ptr = sha_regions; ptr < end; ptr++) 49
50 for (ptr = purgatory_sha_regions; ptr < end; ptr++)
52 sha256_update(&sctx, (uint8_t *)(ptr->start), ptr->len); 51 sha256_update(&sctx, (uint8_t *)(ptr->start), ptr->len);
53 52
54 sha256_final(&sctx, digest); 53 sha256_final(&sctx, digest);
55 54
56 if (memcmp(digest, sha256_digest, sizeof(digest))) 55 if (memcmp(digest, purgatory_sha256_digest, sizeof(digest)))
57 return 1; 56 return 1;
58 57
59 return 0; 58 return 0;
diff --git a/arch/x86/purgatory/purgatory.h b/arch/x86/purgatory/purgatory.h
deleted file mode 100644
index e2e365a6c192..000000000000
--- a/arch/x86/purgatory/purgatory.h
+++ /dev/null
@@ -1,8 +0,0 @@
1#ifndef PURGATORY_H
2#define PURGATORY_H
3
4#ifndef __ASSEMBLY__
5extern void purgatory(void);
6#endif /* __ASSEMBLY__ */
7
8#endif /* PURGATORY_H */
diff --git a/arch/x86/purgatory/setup-x86_64.S b/arch/x86/purgatory/setup-x86_64.S
index f90e9dfa90bb..dfae9b9e60b5 100644
--- a/arch/x86/purgatory/setup-x86_64.S
+++ b/arch/x86/purgatory/setup-x86_64.S
@@ -9,7 +9,7 @@
9 * This source code is licensed under the GNU General Public License, 9 * This source code is licensed under the GNU General Public License,
10 * Version 2. See the file COPYING for more details. 10 * Version 2. See the file COPYING for more details.
11 */ 11 */
12#include "purgatory.h" 12#include <asm/purgatory.h>
13 13
14 .text 14 .text
15 .globl purgatory_start 15 .globl purgatory_start
diff --git a/arch/x86/purgatory/sha256.h b/arch/x86/purgatory/sha256.h
index bd15a4127735..2867d9825a57 100644
--- a/arch/x86/purgatory/sha256.h
+++ b/arch/x86/purgatory/sha256.h
@@ -10,7 +10,6 @@
10#ifndef SHA256_H 10#ifndef SHA256_H
11#define SHA256_H 11#define SHA256_H
12 12
13
14#include <linux/types.h> 13#include <linux/types.h>
15#include <crypto/sha.h> 14#include <crypto/sha.h>
16 15
diff --git a/include/linux/purgatory.h b/include/linux/purgatory.h
new file mode 100644
index 000000000000..d60d4e278609
--- /dev/null
+++ b/include/linux/purgatory.h
@@ -0,0 +1,23 @@
1#ifndef _LINUX_PURGATORY_H
2#define _LINUX_PURGATORY_H
3
4#include <linux/types.h>
5#include <crypto/sha.h>
6#include <uapi/linux/kexec.h>
7
8struct kexec_sha_region {
9 unsigned long start;
10 unsigned long len;
11};
12
13/*
14 * These forward declarations serve two purposes:
15 *
16 * 1) Make sparse happy when checking arch/purgatory
17 * 2) Document that these are required to be global so the symbol
18 * lookup in kexec works
19 */
20extern struct kexec_sha_region purgatory_sha_regions[KEXEC_SEGMENT_MAX];
21extern u8 purgatory_sha256_digest[SHA256_DIGEST_SIZE];
22
23#endif
diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
index b56a558e406d..b118735fea9d 100644
--- a/kernel/kexec_file.c
+++ b/kernel/kexec_file.c
@@ -614,13 +614,13 @@ static int kexec_calculate_store_digests(struct kimage *image)
614 ret = crypto_shash_final(desc, digest); 614 ret = crypto_shash_final(desc, digest);
615 if (ret) 615 if (ret)
616 goto out_free_digest; 616 goto out_free_digest;
617 ret = kexec_purgatory_get_set_symbol(image, "sha_regions", 617 ret = kexec_purgatory_get_set_symbol(image, "purgatory_sha_regions",
618 sha_regions, sha_region_sz, 0); 618 sha_regions, sha_region_sz, 0);
619 if (ret) 619 if (ret)
620 goto out_free_digest; 620 goto out_free_digest;
621 621
622 ret = kexec_purgatory_get_set_symbol(image, "sha256_digest", 622 ret = kexec_purgatory_get_set_symbol(image, "purgatory_sha256_digest",
623 digest, SHA256_DIGEST_SIZE, 0); 623 digest, SHA256_DIGEST_SIZE, 0);
624 if (ret) 624 if (ret)
625 goto out_free_digest; 625 goto out_free_digest;
626 } 626 }
diff --git a/kernel/kexec_internal.h b/kernel/kexec_internal.h
index 4cef7e4706b0..799a8a452187 100644
--- a/kernel/kexec_internal.h
+++ b/kernel/kexec_internal.h
@@ -15,11 +15,7 @@ int kimage_is_destination_range(struct kimage *image,
15extern struct mutex kexec_mutex; 15extern struct mutex kexec_mutex;
16 16
17#ifdef CONFIG_KEXEC_FILE 17#ifdef CONFIG_KEXEC_FILE
18struct kexec_sha_region { 18#include <linux/purgatory.h>
19 unsigned long start;
20 unsigned long len;
21};
22
23void kimage_file_post_load_cleanup(struct kimage *image); 19void kimage_file_post_load_cleanup(struct kimage *image);
24#else /* CONFIG_KEXEC_FILE */ 20#else /* CONFIG_KEXEC_FILE */
25static inline void kimage_file_post_load_cleanup(struct kimage *image) { } 21static inline void kimage_file_post_load_cleanup(struct kimage *image) { }