2022-12-14 01:25:56

by Seija K.

[permalink] [raw]
Subject: [PATCH] arch: change variable types to match those of what is assigned to them

There are many places where "int len = strlen(foo);" is written, just for len to be passed as a parameter of size_t. This causes truncation and then expansion back from int to size_t. Not to mention this is poor logic and needless truncations can add extra unneeded instructions.

This patch aims to fix the worst offenders.

Signed-off-by: Seija Kijin <[email protected]>
---
 arch/arm/mm/mmu.c                      | 30 +++++++++++++-------------
 arch/arm/probes/kprobes/test-core.c    |  8 +++----
 arch/arm/vfp/vfpmodule.c               |  4 ++--
 arch/arm/xen/p2m.c                     |  4 ++--
 arch/mips/alchemy/common/irq.c         |  2 +-
 arch/mips/alchemy/common/prom.c        |  2 +-
 arch/mips/alchemy/devboards/bcsr.c     |  2 +-
 arch/mips/alchemy/devboards/platform.c |  8 +++----
 arch/mips/ar7/prom.c                   |  4 ++--
 arch/mips/boot/compressed/dbg.c        | 14 +++++-------
 arch/mips/fw/arc/cmdline.c             |  4 ++--
 arch/xtensa/platforms/iss/console.c    |  4 ++--
 12 files changed, 41 insertions(+), 45 deletions(-)

diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
index 463fc2a8448f..27f5acb69c3b 100644
--- a/arch/arm/mm/mmu.c
+++ b/arch/arm/mm/mmu.c
@@ -117,7 +117,7 @@ static unsigned long initial_pmd_value __initdata = 0;
  */
 void __init init_default_cache_policy(unsigned long pmd)
 {
-    int i;
+    unsigned i;

     initial_pmd_value = pmd;

@@ -140,20 +140,22 @@ void __init init_default_cache_policy(unsigned long pmd)
  */
 static int __init early_cachepolicy(char *p)
 {
-    int i, selected = -1;
+    size_t i, selected = 0;

     for (i = 0; i < ARRAY_SIZE(cache_policies); i++) {
-        int len = strlen(cache_policies[i].policy);
+        size_t len = strlen(cache_policies[i].policy);

         if (memcmp(p, cache_policies[i].policy, len) == 0) {
             selected = i;
-            break;
+            goto no_err;
         }
     }

-    if (selected == -1)
-        pr_err("ERROR: unknown or unsupported cache policy\n");
+    pr_err("ERROR: unknown or unsupported cache policy\n");

+no_err:
+    if (selected != cachepolicy) {
+        unsigned long cr;
     /*
      * This restriction is partly to do with the way we boot; it is
      * unpredictable to have memory mapped using two different sets of
@@ -161,14 +163,12 @@ static int __init early_cachepolicy(char *p)
      * change these attributes once the initial assembly has setup the
      * page tables.
      */
-    if (cpu_architecture() >= CPU_ARCH_ARMv6 && selected != cachepolicy) {
-        pr_warn("Only cachepolicy=%s supported on ARMv6 and later\n",
-            cache_policies[cachepolicy].policy);
-        return 0;
-    }
-
-    if (selected != cachepolicy) {
-        unsigned long cr = __clear_cr(cache_policies[selected].cr_mask);
+        if (cpu_architecture() >= CPU_ARCH_ARMv6) {
+            pr_warn("Only cachepolicy=%s supported on ARMv6 and later\n",
+                cache_policies[cachepolicy].policy);
+            return 0;
+        }
+        cr = __clear_cr(cache_policies[selected].cr_mask);
         cachepolicy = selected;
         flush_cache_all();
         set_cr(cr);
@@ -445,7 +445,7 @@ static void __init build_mem_type_table(void)
     unsigned int cr = get_cr();
     pteval_t user_pgprot, kern_pgprot, vecs_pgprot;
     int cpu_arch = cpu_architecture();
-    int i;
+    size_t i;

     if (cpu_arch < CPU_ARCH_ARMv6) {
 #if defined(CONFIG_CPU_DCACHE_DISABLE)
diff --git a/arch/arm/probes/kprobes/test-core.c b/arch/arm/probes/kprobes/test-core.c
index c562832b8627..7e8694eb772c 100644
--- a/arch/arm/probes/kprobes/test-core.c
+++ b/arch/arm/probes/kprobes/test-core.c
@@ -723,9 +723,9 @@ static const char coverage_register_lookup[16] = {
 unsigned coverage_start_registers(const struct decode_header *h)
 {
     unsigned regs = 0;
-    int i;
+    unsigned i;
     for (i = 0; i < 20; i += 4) {
-        int r = (h->type_regs.bits >> (DECODE_TYPE_BITS + i)) & 0xf;
+        unsigned r = (h->type_regs.bits >> (DECODE_TYPE_BITS + i)) & 0xf;
         regs |= coverage_register_lookup[r] << i;
     }
     return regs;
@@ -774,12 +774,12 @@ static int coverage_start(const union decode_item *table)
 static void
 coverage_add_registers(struct coverage_entry *entry, kprobe_opcode_t insn)
 {
-    int regs = entry->header->type_regs.bits >> DECODE_TYPE_BITS;
+    u32 regs = entry->header->type_regs.bits >> DECODE_TYPE_BITS;
     int i;
     for (i = 0; i < 20; i += 4) {
         enum decode_reg_type reg_type = (regs >> i) & 0xf;
         int reg = (insn >> i) & 0xf;
-        int flag;
+        unsigned flag;

         if (!reg_type)
             continue;
diff --git a/arch/arm/vfp/vfpmodule.c b/arch/arm/vfp/vfpmodule.c
index 2cb355c1b5b7..c491ed8e5cf2 100644
--- a/arch/arm/vfp/vfpmodule.c
+++ b/arch/arm/vfp/vfpmodule.c
@@ -227,7 +227,7 @@ static void vfp_raise_sigfpe(unsigned int sicode, struct pt_regs *regs)

 static void vfp_panic(char *reason, u32 inst)
 {
-    int i;
+    unsigned i;

     pr_err("VFP: Error: %s\n", reason);
     pr_err("VFP: EXC 0x%08x SCR 0x%08x INST 0x%08x\n",
@@ -700,7 +700,7 @@ static struct undef_hook vfp_kmode_exception_hook[] = {{

 static int __init vfp_kmode_exception_hook_init(void)
 {
-    int i;
+    size_t i;

     for (i = 0; i < ARRAY_SIZE(vfp_kmode_exception_hook); i++)
         register_undef_hook(&vfp_kmode_exception_hook[i]);
diff --git a/arch/arm/xen/p2m.c b/arch/arm/xen/p2m.c
index 309648c17f48..7417da4d1236 100644
--- a/arch/arm/xen/p2m.c
+++ b/arch/arm/xen/p2m.c
@@ -92,7 +92,7 @@ int set_foreign_p2m_mapping(struct gnttab_map_grant_ref *map_ops,
                 struct gnttab_map_grant_ref *kmap_ops,
                 struct page **pages, unsigned int count)
 {
-    int i;
+    unsigned i;

     for (i = 0; i < count; i++) {
         struct gnttab_unmap_grant_ref unmap;
@@ -137,7 +137,7 @@ int clear_foreign_p2m_mapping(struct gnttab_unmap_grant_ref *unmap_ops,
                   struct gnttab_unmap_grant_ref *kunmap_ops,
                   struct page **pages, unsigned int count)
 {
-    int i;
+    unsigned i;

     for (i = 0; i < count; i++) {
         set_phys_to_machine(unmap_ops[i].host_addr >> XEN_PAGE_SHIFT,
diff --git a/arch/mips/alchemy/common/irq.c b/arch/mips/alchemy/common/irq.c
index da9f9220048f..83f73ae7d225 100644
--- a/arch/mips/alchemy/common/irq.c
+++ b/arch/mips/alchemy/common/irq.c
@@ -809,7 +809,7 @@ static int alchemy_gpic_suspend(void)
 static void alchemy_gpic_resume(void)
 {
     void __iomem *base = (void __iomem *)KSEG1ADDR(AU1300_GPIC_PHYS_ADDR);
-    int i;
+    u32 i;

     /* disable all first */
     __raw_writel(~0UL, base + AU1300_GPIC_IDIS + 0x0);
diff --git a/arch/mips/alchemy/common/prom.c b/arch/mips/alchemy/common/prom.c
index b13d8adf3be4..7b28b9ce1d3a 100644
--- a/arch/mips/alchemy/common/prom.c
+++ b/arch/mips/alchemy/common/prom.c
@@ -111,7 +111,7 @@ static inline unsigned char str2hexnum(unsigned char c)

 static inline void str2eaddr(unsigned char *ea, unsigned char *str)
 {
-    int i;
+    unsigned i;

     for (i = 0; i < 6; i++) {
         unsigned char num;
diff --git a/arch/mips/alchemy/devboards/bcsr.c b/arch/mips/alchemy/devboards/bcsr.c
index 8df0ccdc9287..894916e95ff6 100644
--- a/arch/mips/alchemy/devboards/bcsr.c
+++ b/arch/mips/alchemy/devboards/bcsr.c
@@ -28,7 +28,7 @@ static int bcsr_csc_base;    /* linux-irq of first cascaded irq */

 void __init bcsr_init(unsigned long bcsr1_phys, unsigned long bcsr2_phys)
 {
-    int i;
+    unsigned i;

     bcsr1_phys = KSEG1ADDR(CPHYSADDR(bcsr1_phys));
     bcsr2_phys = KSEG1ADDR(CPHYSADDR(bcsr2_phys));
diff --git a/arch/mips/alchemy/devboards/platform.c b/arch/mips/alchemy/devboards/platform.c
index 754bdd2ca630..a69d9d56f130 100644
--- a/arch/mips/alchemy/devboards/platform.c
+++ b/arch/mips/alchemy/devboards/platform.c
@@ -122,10 +122,10 @@ int __init db1x_register_pcmcia_socket(phys_addr_t pcmcia_attr_start,

     i = 5;
     if (stschg_irq) {
-        sr[i].name    = "stschg";
-        sr[i].flags    = IORESOURCE_IRQ;
-        sr[i].start = sr[i].end = stschg_irq;
-        i++;
+        sr[5].name    = "stschg";
+        sr[5].flags    = IORESOURCE_IRQ;
+        sr[5].start = sr[5].end = stschg_irq;
+        i = 6;
     }
     if (eject_irq) {
         sr[i].name    = "eject";
diff --git a/arch/mips/ar7/prom.c b/arch/mips/ar7/prom.c
index 5810d3993fc6..dda3ed6934ac 100644
--- a/arch/mips/ar7/prom.c
+++ b/arch/mips/ar7/prom.c
@@ -144,7 +144,7 @@ static void __init add_adam2_var(char *name, char *value)

 static int __init parse_psp_env(void *psp_env_base)
 {
-    int i, n;
+    unsigned i, n;
     char *name, *value;
     struct psp_env_chunk *chunks = (struct psp_env_chunk *)psp_env_data;

@@ -171,7 +171,7 @@ static int __init parse_psp_env(void *psp_env_base)

 static void __init ar7_init_env(struct env_var *env)
 {
-    int i;
+    unsigned i;
     struct psbl_rec *psbl = (struct psbl_rec *)(KSEG1ADDR(0x14000300));
     void *psp_env = (void *)KSEG1ADDR(psbl->env_base);

diff --git a/arch/mips/boot/compressed/dbg.c b/arch/mips/boot/compressed/dbg.c
index f6728a8fd1c3..5957f9030e0c 100644
--- a/arch/mips/boot/compressed/dbg.c
+++ b/arch/mips/boot/compressed/dbg.c
@@ -25,13 +25,9 @@ void puts(const char *s)

 void puthex(unsigned long long val)
 {
-
-    unsigned char buf[10];
-    int i;
-    for (i = 7; i >= 0; i--) {
-        buf[i] = "0123456789ABCDEF"[val & 0x0F];
-        val >>= 4;
-    }
-    buf[8] = '\0';
-    puts(buf);
+    char buf[9];
+    size_t i = sizeof(buf) - 1;
+    for (buf[i] = '\0'; i; val >>= 4)
+        buf[--i] = "0123456789ABCDEF"[val & 0xF];
+    puts(buf);
 }
diff --git a/arch/mips/fw/arc/cmdline.c b/arch/mips/fw/arc/cmdline.c
index 155c5e911723..5b05069fec8f 100644
--- a/arch/mips/fw/arc/cmdline.c
+++ b/arch/mips/fw/arc/cmdline.c
@@ -47,7 +47,7 @@ static char __init *move_firmware_args(int argc, LONG *argv, char *cp)

     while (actr < argc) {
         for(i = 0; i < ARRAY_SIZE(used_arc); i++) {
-            int len = strlen(used_arc[i][0]);
+            size_t len = strlen(used_arc[i][0]);

             if (!strncmp(prom_argv(actr), used_arc[i][0], len)) {
             /* Ok, we want it. First append the replacement... */
@@ -86,7 +86,7 @@ void __init prom_init_cmdline(int argc, LONG *argv)

     while (actr < argc) {
         for (i = 0; i < ARRAY_SIZE(ignored); i++) {
-            int len = strlen(ignored[i]);
+            size_t len = strlen(ignored[i]);

             if (!strncmp(prom_argv(actr), ignored[i], len))
                 goto pic_cont;
diff --git a/arch/xtensa/platforms/iss/console.c b/arch/xtensa/platforms/iss/console.c
index 10b79d3c74e0..3159917ffd2f 100644
--- a/arch/xtensa/platforms/iss/console.c
+++ b/arch/xtensa/platforms/iss/console.c
@@ -64,7 +64,7 @@ static int rs_write(struct tty_struct * tty,
 static void rs_poll(struct timer_list *unused)
 {
     struct tty_port *port = &serial_port;
-    int i = 0;
+    size_t i = 0;
     int rd = 1;
     unsigned char c;

@@ -192,7 +192,7 @@ late_initcall(rs_init);
 static void iss_console_write(struct console *co, const char *s, unsigned count)
 {
     if (s && *s != 0) {
-        int len = strlen(s);
+        size_t len = strlen(s);
         simc_write(1, s, count < len ? count : len);
     }
 }
--
2.38.2



2022-12-14 02:02:25

by Max Filippov

[permalink] [raw]
Subject: Re: [PATCH] arch: change variable types to match those of what is assigned to them

Hi Seija,

On Tue, Dec 13, 2022 at 4:51 PM Seija Kijin <[email protected]> wrote:
>
> There are many places where "int len = strlen(foo);" is written, just for len to be passed as a parameter of size_t.

[...]

> diff --git a/arch/xtensa/platforms/iss/console.c b/arch/xtensa/platforms/iss/console.c
> index 10b79d3c74e0..3159917ffd2f 100644
> --- a/arch/xtensa/platforms/iss/console.c
> +++ b/arch/xtensa/platforms/iss/console.c
> @@ -64,7 +64,7 @@ static int rs_write(struct tty_struct * tty,
> static void rs_poll(struct timer_list *unused)
> {
> struct tty_port *port = &serial_port;
> - int i = 0;
> + size_t i = 0;

This is not what happens here at all.

--
Thanks.
-- Max