[PATCH v2] x86/cacheinfo: fix a -Wtype-limits warning

[PATCH v2] x86/cacheinfo: fix a -Wtype-limits warning

[Qian Cai]

cpuinfo_x86.x86_model is an unsigned type, so compares it against zero
will generate a compilation warning,

arch/x86/kernel/cpu/cacheinfo.c: In function
'cacheinfo_amd_init_llc_id':
arch/x86/kernel/cpu/cacheinfo.c:662:19: warning: comparison is always
true due to limited range of data type [-Wtype-limits]

"c->x86 == 0x17" is true if and only if c->x86_model was explicitly set
by cpu_detect(), so just remove the unnecessary checking.

Fixes: 68091ee7ac3c ("x86/CPU/AMD: Calculate last level cache ID from number of sharing threads")
Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Qian Cai <cai@lca.pw>
---

v2: Update the commit message per Sean.

 arch/x86/kernel/cpu/cacheinfo.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/arch/x86/kernel/cpu/cacheinfo.c b/arch/x86/kernel/cpu/cacheinfo.c
index 395d46f78582..c7503be92f35 100644
--- a/arch/x86/kernel/cpu/cacheinfo.c
+++ b/arch/x86/kernel/cpu/cacheinfo.c
@@ -658,8 +658,7 @@ void cacheinfo_amd_init_llc_id(struct cpuinfo_x86 *c, int cpu, u8 node_id)
 	if (c->x86 < 0x17) {
 		/* LLC is at the node level. */
 		per_cpu(cpu_llc_id, cpu) = node_id;
-	} else if (c->x86 == 0x17 &&
-		   c->x86_model >= 0 && c->x86_model <= 0x1F) {
+	} else if (c->x86 == 0x17 && c->x86_model <= 0x1F) {
 		/*
 		 * LLC is at the core complex level.
 		 * Core complex ID is ApicId[3] for these processors.
-- 
1.8.3.1

[tip:x86/cpu] x86/cacheinfo: Fix a -Wtype-limits warning

[tip-bot for Qian Cai]

Commit-ID:  1b7aebf0487613033aff26420e32fa2076d52846
Gitweb:     https://git.kernel.org/tip/1b7aebf0487613033aff26420e32fa2076d52846
Author:     Qian Cai <cai@lca.pw>
AuthorDate: Wed, 19 Jun 2019 10:32:53 -0400
Committer:  Borislav Petkov <bp@suse.de>
CommitDate: Wed, 19 Jun 2019 19:21:32 +0200

x86/cacheinfo: Fix a -Wtype-limits warning

cpuinfo_x86.x86_model is an unsigned type, so comparing against zero
will generate a compilation warning:

  arch/x86/kernel/cpu/cacheinfo.c: In function 'cacheinfo_amd_init_llc_id':
  arch/x86/kernel/cpu/cacheinfo.c:662:19: warning: comparison is always true \
    due to limited range of data type [-Wtype-limits]

Remove the unnecessary lower bound check.

 [ bp: Massage. ]

Fixes: 68091ee7ac3c ("x86/CPU/AMD: Calculate last level cache ID from number of sharing threads")
Signed-off-by: Qian Cai <cai@lca.pw>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: "Gustavo A. R. Silva" <gustavo@embeddedor.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Pu Wen <puwen@hygon.cn>
Cc: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: x86-ml <x86@kernel.org>
Link: https://lkml.kernel.org/r/1560954773-11967-1-git-send-email-cai@lca.pw
---
 arch/x86/kernel/cpu/cacheinfo.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/arch/x86/kernel/cpu/cacheinfo.c b/arch/x86/kernel/cpu/cacheinfo.c
index 395d46f78582..c7503be92f35 100644
--- a/arch/x86/kernel/cpu/cacheinfo.c
+++ b/arch/x86/kernel/cpu/cacheinfo.c
@@ -658,8 +658,7 @@ void cacheinfo_amd_init_llc_id(struct cpuinfo_x86 *c, int cpu, u8 node_id)
 	if (c->x86 < 0x17) {
 		/* LLC is at the node level. */
 		per_cpu(cpu_llc_id, cpu) = node_id;
-	} else if (c->x86 == 0x17 &&
-		   c->x86_model >= 0 && c->x86_model <= 0x1F) {
+	} else if (c->x86 == 0x17 && c->x86_model <= 0x1F) {
 		/*
 		 * LLC is at the core complex level.
 		 * Core complex ID is ApicId[3] for these processors.