Re: [PATCH v10 05/18] powerpc/prom_init: don't use string functions from lib/

From: Christophe Leroy
Date: Fri Apr 26 2019 - 12:24:13 EST




Le 13/03/2019 Ã 00:38, Daniel Axtens a ÃcritÂ:
Hi Christophe,

In trying to extend my KASAN implementation to Book3S 64bit, I found one
other change needed to prom_init. I don't know if you think it should go
in this patch, the next one, or somewhere else entirely - I will leave
it up to you. Just let me know if you want me to carry it separately.

Taken in patch 5 in v11.

Christophe


Thanks again for all your work on this and the integration of my series.

Regards,
Daniel

diff --git a/arch/powerpc/kernel/prom_init.c b/arch/powerpc/kernel/prom_init.c
index 7017156168e8..cebb3fc535ba 100644
--- a/arch/powerpc/kernel/prom_init.c
+++ b/arch/powerpc/kernel/prom_init.c
@@ -1265,7 +1265,8 @@ static void __init prom_check_platform_support(void)
"ibm,arch-vec-5-platform-support");
/* First copy the architecture vec template */
- ibm_architecture_vec = ibm_architecture_vec_template;
+ memcpy(&ibm_architecture_vec, &ibm_architecture_vec_template,
+ sizeof(struct ibm_arch_vec));
if (prop_len > 1) {
int i;

When KASAN is active, the string functions in lib/ are doing the
KASAN checks. This is too early for prom_init.

This patch implements dedicated string functions for prom_init,
which will be compiled in with KASAN disabled.

Size of prom_init before the patch:
text data bss dec hex filename
12060 488 6960 19508 4c34 arch/powerpc/kernel/prom_init.o

Size of prom_init after the patch:
text data bss dec hex filename
12460 488 6960 19908 4dc4 arch/powerpc/kernel/prom_init.o

This increases the size of prom_init a bit, but as prom_init is
in __init section, it is freed after boot anyway.

Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxx>
---
arch/powerpc/kernel/prom_init.c | 211 ++++++++++++++++++++++++++-------
arch/powerpc/kernel/prom_init_check.sh | 2 +-
2 files changed, 171 insertions(+), 42 deletions(-)

diff --git a/arch/powerpc/kernel/prom_init.c b/arch/powerpc/kernel/prom_init.c
index ecf083c46bdb..7017156168e8 100644
--- a/arch/powerpc/kernel/prom_init.c
+++ b/arch/powerpc/kernel/prom_init.c
@@ -224,6 +224,135 @@ static bool __prombss rtas_has_query_cpu_stopped;
#define PHANDLE_VALID(p) ((p) != 0 && (p) != PROM_ERROR)
#define IHANDLE_VALID(i) ((i) != 0 && (i) != PROM_ERROR)
+/* Copied from lib/string.c and lib/kstrtox.c */
+
+static int __init prom_strcmp(const char *cs, const char *ct)
+{
+ unsigned char c1, c2;
+
+ while (1) {
+ c1 = *cs++;
+ c2 = *ct++;
+ if (c1 != c2)
+ return c1 < c2 ? -1 : 1;
+ if (!c1)
+ break;
+ }
+ return 0;
+}
+
+static char __init *prom_strcpy(char *dest, const char *src)
+{
+ char *tmp = dest;
+
+ while ((*dest++ = *src++) != '\0')
+ /* nothing */;
+ return tmp;
+}
+
+static int __init prom_strncmp(const char *cs, const char *ct, size_t count)
+{
+ unsigned char c1, c2;
+
+ while (count) {
+ c1 = *cs++;
+ c2 = *ct++;
+ if (c1 != c2)
+ return c1 < c2 ? -1 : 1;
+ if (!c1)
+ break;
+ count--;
+ }
+ return 0;
+}
+
+static size_t __init prom_strlen(const char *s)
+{
+ const char *sc;
+
+ for (sc = s; *sc != '\0'; ++sc)
+ /* nothing */;
+ return sc - s;
+}
+
+static int __init prom_memcmp(const void *cs, const void *ct, size_t count)
+{
+ const unsigned char *su1, *su2;
+ int res = 0;
+
+ for (su1 = cs, su2 = ct; 0 < count; ++su1, ++su2, count--)
+ if ((res = *su1 - *su2) != 0)
+ break;
+ return res;
+}
+
+static char __init *prom_strstr(const char *s1, const char *s2)
+{
+ size_t l1, l2;
+
+ l2 = prom_strlen(s2);
+ if (!l2)
+ return (char *)s1;
+ l1 = prom_strlen(s1);
+ while (l1 >= l2) {
+ l1--;
+ if (!prom_memcmp(s1, s2, l2))
+ return (char *)s1;
+ s1++;
+ }
+ return NULL;
+}
+
+static size_t __init prom_strlcpy(char *dest, const char *src, size_t size)
+{
+ size_t ret = prom_strlen(src);
+
+ if (size) {
+ size_t len = (ret >= size) ? size - 1 : ret;
+ memcpy(dest, src, len);
+ dest[len] = '\0';
+ }
+ return ret;
+}
+
+#ifdef CONFIG_PPC_PSERIES
+static int __init prom_strtobool(const char *s, bool *res)
+{
+ if (!s)
+ return -EINVAL;
+
+ switch (s[0]) {
+ case 'y':
+ case 'Y':
+ case '1':
+ *res = true;
+ return 0;
+ case 'n':
+ case 'N':
+ case '0':
+ *res = false;
+ return 0;
+ case 'o':
+ case 'O':
+ switch (s[1]) {
+ case 'n':
+ case 'N':
+ *res = true;
+ return 0;
+ case 'f':
+ case 'F':
+ *res = false;
+ return 0;
+ default:
+ break;
+ }
+ default:
+ break;
+ }
+
+ return -EINVAL;
+}
+#endif
/* This is the one and *ONLY* place where we actually call open
* firmware.
@@ -555,7 +684,7 @@ static int __init prom_setprop(phandle node, const char *nodename,
add_string(&p, tohex((u32)(unsigned long) value));
add_string(&p, tohex(valuelen));
add_string(&p, tohex(ADDR(pname)));
- add_string(&p, tohex(strlen(pname)));
+ add_string(&p, tohex(prom_strlen(pname)));
add_string(&p, "property");
*p = 0;
return call_prom("interpret", 1, 1, (u32)(unsigned long) cmd);
@@ -638,23 +767,23 @@ static void __init early_cmdline_parse(void)
if ((long)prom.chosen > 0)
l = prom_getprop(prom.chosen, "bootargs", p, COMMAND_LINE_SIZE-1);
if (IS_ENABLED(CONFIG_CMDLINE_BOOL) && (l <= 0 || p[0] == '\0')) /* dbl check */
- strlcpy(prom_cmd_line, CONFIG_CMDLINE, sizeof(prom_cmd_line));
+ prom_strlcpy(prom_cmd_line, CONFIG_CMDLINE, sizeof(prom_cmd_line));
prom_printf("command line: %s\n", prom_cmd_line);
#ifdef CONFIG_PPC64
- opt = strstr(prom_cmd_line, "iommu=");
+ opt = prom_strstr(prom_cmd_line, "iommu=");
if (opt) {
prom_printf("iommu opt is: %s\n", opt);
opt += 6;
while (*opt && *opt == ' ')
opt++;
- if (!strncmp(opt, "off", 3))
+ if (!prom_strncmp(opt, "off", 3))
prom_iommu_off = 1;
- else if (!strncmp(opt, "force", 5))
+ else if (!prom_strncmp(opt, "force", 5))
prom_iommu_force_on = 1;
}
#endif
- opt = strstr(prom_cmd_line, "mem=");
+ opt = prom_strstr(prom_cmd_line, "mem=");
if (opt) {
opt += 4;
prom_memory_limit = prom_memparse(opt, (const char **)&opt);
@@ -666,13 +795,13 @@ static void __init early_cmdline_parse(void)
#ifdef CONFIG_PPC_PSERIES
prom_radix_disable = !IS_ENABLED(CONFIG_PPC_RADIX_MMU_DEFAULT);
- opt = strstr(prom_cmd_line, "disable_radix");
+ opt = prom_strstr(prom_cmd_line, "disable_radix");
if (opt) {
opt += 13;
if (*opt && *opt == '=') {
bool val;
- if (kstrtobool(++opt, &val))
+ if (prom_strtobool(++opt, &val))
prom_radix_disable = false;
else
prom_radix_disable = val;
@@ -1025,7 +1154,7 @@ static int __init prom_count_smt_threads(void)
type[0] = 0;
prom_getprop(node, "device_type", type, sizeof(type));
- if (strcmp(type, "cpu"))
+ if (prom_strcmp(type, "cpu"))
continue;
/*
* There is an entry for each smt thread, each entry being
@@ -1472,7 +1601,7 @@ static void __init prom_init_mem(void)
*/
prom_getprop(node, "name", type, sizeof(type));
}
- if (strcmp(type, "memory"))
+ if (prom_strcmp(type, "memory"))
continue;
plen = prom_getprop(node, "reg", regbuf, sizeof(regbuf));
@@ -1753,19 +1882,19 @@ static void __init prom_initialize_tce_table(void)
prom_getprop(node, "device_type", type, sizeof(type));
prom_getprop(node, "model", model, sizeof(model));
- if ((type[0] == 0) || (strstr(type, "pci") == NULL))
+ if ((type[0] == 0) || (prom_strstr(type, "pci") == NULL))
continue;
/* Keep the old logic intact to avoid regression. */
if (compatible[0] != 0) {
- if ((strstr(compatible, "python") == NULL) &&
- (strstr(compatible, "Speedwagon") == NULL) &&
- (strstr(compatible, "Winnipeg") == NULL))
+ if ((prom_strstr(compatible, "python") == NULL) &&
+ (prom_strstr(compatible, "Speedwagon") == NULL) &&
+ (prom_strstr(compatible, "Winnipeg") == NULL))
continue;
} else if (model[0] != 0) {
- if ((strstr(model, "ython") == NULL) &&
- (strstr(model, "peedwagon") == NULL) &&
- (strstr(model, "innipeg") == NULL))
+ if ((prom_strstr(model, "ython") == NULL) &&
+ (prom_strstr(model, "peedwagon") == NULL) &&
+ (prom_strstr(model, "innipeg") == NULL))
continue;
}
@@ -1914,12 +2043,12 @@ static void __init prom_hold_cpus(void)
type[0] = 0;
prom_getprop(node, "device_type", type, sizeof(type));
- if (strcmp(type, "cpu") != 0)
+ if (prom_strcmp(type, "cpu") != 0)
continue;
/* Skip non-configured cpus. */
if (prom_getprop(node, "status", type, sizeof(type)) > 0)
- if (strcmp(type, "okay") != 0)
+ if (prom_strcmp(type, "okay") != 0)
continue;
reg = cpu_to_be32(-1); /* make sparse happy */
@@ -1995,9 +2124,9 @@ static void __init prom_find_mmu(void)
return;
version[sizeof(version) - 1] = 0;
/* XXX might need to add other versions here */
- if (strcmp(version, "Open Firmware, 1.0.5") == 0)
+ if (prom_strcmp(version, "Open Firmware, 1.0.5") == 0)
of_workarounds = OF_WA_CLAIM;
- else if (strncmp(version, "FirmWorks,3.", 12) == 0) {
+ else if (prom_strncmp(version, "FirmWorks,3.", 12) == 0) {
of_workarounds = OF_WA_CLAIM | OF_WA_LONGTRAIL;
call_prom("interpret", 1, 1, "dev /memory 0 to allow-reclaim");
} else
@@ -2030,7 +2159,7 @@ static void __init prom_init_stdout(void)
call_prom("instance-to-path", 3, 1, prom.stdout, path, 255);
prom_printf("OF stdout device is: %s\n", of_stdout_device);
prom_setprop(prom.chosen, "/chosen", "linux,stdout-path",
- path, strlen(path) + 1);
+ path, prom_strlen(path) + 1);
/* instance-to-package fails on PA-Semi */
stdout_node = call_prom("instance-to-package", 1, 1, prom.stdout);
@@ -2040,7 +2169,7 @@ static void __init prom_init_stdout(void)
/* If it's a display, note it */
memset(type, 0, sizeof(type));
prom_getprop(stdout_node, "device_type", type, sizeof(type));
- if (strcmp(type, "display") == 0)
+ if (prom_strcmp(type, "display") == 0)
prom_setprop(stdout_node, path, "linux,boot-display", NULL, 0);
}
}
@@ -2061,19 +2190,19 @@ static int __init prom_find_machine_type(void)
compat[len] = 0;
while (i < len) {
char *p = &compat[i];
- int sl = strlen(p);
+ int sl = prom_strlen(p);
if (sl == 0)
break;
- if (strstr(p, "Power Macintosh") ||
- strstr(p, "MacRISC"))
+ if (prom_strstr(p, "Power Macintosh") ||
+ prom_strstr(p, "MacRISC"))
return PLATFORM_POWERMAC;
#ifdef CONFIG_PPC64
/* We must make sure we don't detect the IBM Cell
* blades as pSeries due to some firmware issues,
* so we do it here.
*/
- if (strstr(p, "IBM,CBEA") ||
- strstr(p, "IBM,CPBW-1.0"))
+ if (prom_strstr(p, "IBM,CBEA") ||
+ prom_strstr(p, "IBM,CPBW-1.0"))
return PLATFORM_GENERIC;
#endif /* CONFIG_PPC64 */
i += sl + 1;
@@ -2090,7 +2219,7 @@ static int __init prom_find_machine_type(void)
compat, sizeof(compat)-1);
if (len <= 0)
return PLATFORM_GENERIC;
- if (strcmp(compat, "chrp"))
+ if (prom_strcmp(compat, "chrp"))
return PLATFORM_GENERIC;
/* Default to pSeries. We need to know if we are running LPAR */
@@ -2152,7 +2281,7 @@ static void __init prom_check_displays(void)
for (node = 0; prom_next_node(&node); ) {
memset(type, 0, sizeof(type));
prom_getprop(node, "device_type", type, sizeof(type));
- if (strcmp(type, "display") != 0)
+ if (prom_strcmp(type, "display") != 0)
continue;
/* It seems OF doesn't null-terminate the path :-( */
@@ -2256,9 +2385,9 @@ static unsigned long __init dt_find_string(char *str)
s = os = (char *)dt_string_start;
s += 4;
while (s < (char *)dt_string_end) {
- if (strcmp(s, str) == 0)
+ if (prom_strcmp(s, str) == 0)
return s - os;
- s += strlen(s) + 1;
+ s += prom_strlen(s) + 1;
}
return 0;
}
@@ -2291,7 +2420,7 @@ static void __init scan_dt_build_strings(phandle node,
}
/* skip "name" */
- if (strcmp(namep, "name") == 0) {
+ if (prom_strcmp(namep, "name") == 0) {
*mem_start = (unsigned long)namep;
prev_name = "name";
continue;
@@ -2303,7 +2432,7 @@ static void __init scan_dt_build_strings(phandle node,
namep = sstart + soff;
} else {
/* Trim off some if we can */
- *mem_start = (unsigned long)namep + strlen(namep) + 1;
+ *mem_start = (unsigned long)namep + prom_strlen(namep) + 1;
dt_string_end = *mem_start;
}
prev_name = namep;
@@ -2372,7 +2501,7 @@ static void __init scan_dt_build_struct(phandle node, unsigned long *mem_start,
break;
/* skip "name" */
- if (strcmp(pname, "name") == 0) {
+ if (prom_strcmp(pname, "name") == 0) {
prev_name = "name";
continue;
}
@@ -2403,7 +2532,7 @@ static void __init scan_dt_build_struct(phandle node, unsigned long *mem_start,
call_prom("getprop", 4, 1, node, pname, valp, l);
*mem_start = _ALIGN(*mem_start, 4);
- if (!strcmp(pname, "phandle"))
+ if (!prom_strcmp(pname, "phandle"))
has_phandle = 1;
}
@@ -2473,8 +2602,8 @@ static void __init flatten_device_tree(void)
/* Add "phandle" in there, we'll need it */
namep = make_room(&mem_start, &mem_end, 16, 1);
- strcpy(namep, "phandle");
- mem_start = (unsigned long)namep + strlen(namep) + 1;
+ prom_strcpy(namep, "phandle");
+ mem_start = (unsigned long)namep + prom_strlen(namep) + 1;
/* Build string array */
prom_printf("Building dt strings...\n");
@@ -2796,7 +2925,7 @@ static void __init fixup_device_tree_efika(void)
rv = prom_getprop(node, "model", prop, sizeof(prop));
if (rv == PROM_ERROR)
return;
- if (strcmp(prop, "EFIKA5K2"))
+ if (prom_strcmp(prop, "EFIKA5K2"))
return;
prom_printf("Applying EFIKA device tree fixups\n");
@@ -2804,13 +2933,13 @@ static void __init fixup_device_tree_efika(void)
/* Claiming to be 'chrp' is death */
node = call_prom("finddevice", 1, 1, ADDR("/"));
rv = prom_getprop(node, "device_type", prop, sizeof(prop));
- if (rv != PROM_ERROR && (strcmp(prop, "chrp") == 0))
+ if (rv != PROM_ERROR && (prom_strcmp(prop, "chrp") == 0))
prom_setprop(node, "/", "device_type", "efika", sizeof("efika"));
/* CODEGEN,description is exposed in /proc/cpuinfo so
fix that too */
rv = prom_getprop(node, "CODEGEN,description", prop, sizeof(prop));
- if (rv != PROM_ERROR && (strstr(prop, "CHRP")))
+ if (rv != PROM_ERROR && (prom_strstr(prop, "CHRP")))
prom_setprop(node, "/", "CODEGEN,description",
"Efika 5200B PowerPC System",
sizeof("Efika 5200B PowerPC System"));
diff --git a/arch/powerpc/kernel/prom_init_check.sh b/arch/powerpc/kernel/prom_init_check.sh
index 181fd10008ef..4cac45cb5de5 100644
--- a/arch/powerpc/kernel/prom_init_check.sh
+++ b/arch/powerpc/kernel/prom_init_check.sh
@@ -27,7 +27,7 @@ fi
WHITELIST="add_reloc_offset __bss_start __bss_stop copy_and_flush
_end enter_prom $MEM_FUNCS reloc_offset __secondary_hold
__secondary_hold_acknowledge __secondary_hold_spinloop __start
-strcmp strcpy strlcpy strlen strncmp strstr kstrtobool logo_linux_clut224
+logo_linux_clut224
reloc_got2 kernstart_addr memstart_addr linux_banner _stext
__prom_init_toc_start __prom_init_toc_end btext_setup_display TOC."
--
2.13.3