2020-09-08 11:21:58

by Tony W Wang-oc

Subject: [PATCH v1 0/2] add Centaur Family >= 7 CPUs support

New Centaur CPUs have Family >= 7. So, add specific initialization
for these CPUs in centaur.c

In order to handle Family >= 7, also use if instead two-condition
switch-case in centaur.c

Tony W Wang-oc (2):
x86/cpu: replace two-condition switch-case with if statement
x86/cpu: add Centaur Family >=7 CPUs initialization support

arch/x86/kernel/cpu/centaur.c | 27 ++++++++++++---------------
1 file changed, 12 insertions(+), 15 deletions(-)

--
2.7.4

2020-09-08 13:37:55

by Tony W Wang-oc

Subject: [PATCH v1 1/2] x86/cpu: replace two-condition switch-case with if statement

Use if-case instead two-condition switch-case.

Signed-off-by: Tony W Wang-oc <[email protected]>
---
arch/x86/kernel/cpu/centaur.c | 23 ++++++++---------------
1 file changed, 8 insertions(+), 15 deletions(-)

diff --git a/arch/x86/kernel/cpu/centaur.c b/arch/x86/kernel/cpu/centaur.c
index c5cf336..5f811586 100644
--- a/arch/x86/kernel/cpu/centaur.c
+++ b/arch/x86/kernel/cpu/centaur.c
@@ -90,18 +90,14 @@ enum {

static void early_init_centaur(struct cpuinfo_x86 *c)
{
- switch (c->x86) {
#ifdef CONFIG_X86_32
- case 5:
- /* Emulate MTRRs using Centaur's MCR. */
+ /* Emulate MTRRs using Centaur's MCR. */
+ if (c->x86 == 5)
set_cpu_cap(c, X86_FEATURE_CENTAUR_MCR);
- break;
#endif
- case 6:
- if (c->x86_model >= 0xf)
- set_cpu_cap(c, X86_FEATURE_CONSTANT_TSC);
- break;
- }
+ if (c->x86 == 6 && c->x86_model >= 0xf)
+ set_cpu_cap(c, X86_FEATURE_CONSTANT_TSC);
+
#ifdef CONFIG_X86_64
set_cpu_cap(c, X86_FEATURE_SYSENTER32);
#endif
@@ -145,9 +141,8 @@ static void init_centaur(struct cpuinfo_x86 *c)
set_cpu_cap(c, X86_FEATURE_ARCH_PERFMON);
}

- switch (c->x86) {
#ifdef CONFIG_X86_32
- case 5:
+ if (c->x86 == 5) {
switch (c->x86_model) {
case 4:
name = "C6";
@@ -207,12 +202,10 @@ static void init_centaur(struct cpuinfo_x86 *c)
c->x86_cache_size = (cc>>24)+(dd>>24);
}
sprintf(c->x86_model_id, "WinChip %s", name);
- break;
+ }
#endif
- case 6:
+ if (c->x86 == 6)
init_c3(c);
- break;
- }
#ifdef CONFIG_X86_64
set_cpu_cap(c, X86_FEATURE_LFENCE_RDTSC);
#endif
--
2.7.4

2020-09-11 09:48:54

by tip-bot2 for Jacob Pan

Subject: [tip: x86/cpu] x86/cpu/centaur: Replace two-condition switch-case with an if statement

The following commit has been merged into the x86/cpu branch of tip:

Commit-ID: 8687bdc04128b2bd16faaae11db10128ad0da7b8
Gitweb: https://git.kernel.org/tip/8687bdc04128b2bd16faaae11db10128ad0da7b8
Author: Tony W Wang-oc <[email protected]>
AuthorDate: Tue, 08 Sep 2020 18:57:45 +08:00
Committer: Borislav Petkov <[email protected]>
CommitterDate: Fri, 11 Sep 2020 10:50:01 +02:00

x86/cpu/centaur: Replace two-condition switch-case with an if statement

Use a normal if statements instead of a two-condition switch-case.

[ bp: Massage commit message. ]

Signed-off-by: Tony W Wang-oc <[email protected]>
Signed-off-by: Borislav Petkov <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
---
arch/x86/kernel/cpu/centaur.c | 23 ++++++++---------------
1 file changed, 8 insertions(+), 15 deletions(-)

diff --git a/arch/x86/kernel/cpu/centaur.c b/arch/x86/kernel/cpu/centaur.c
index c5cf336..5f81158 100644
--- a/arch/x86/kernel/cpu/centaur.c
+++ b/arch/x86/kernel/cpu/centaur.c
@@ -90,18 +90,14 @@ enum {

static void early_init_centaur(struct cpuinfo_x86 *c)
{
- switch (c->x86) {
#ifdef CONFIG_X86_32
- case 5:
- /* Emulate MTRRs using Centaur's MCR. */
+ /* Emulate MTRRs using Centaur's MCR. */
+ if (c->x86 == 5)
set_cpu_cap(c, X86_FEATURE_CENTAUR_MCR);
- break;
#endif
- case 6:
- if (c->x86_model >= 0xf)
- set_cpu_cap(c, X86_FEATURE_CONSTANT_TSC);
- break;
- }
+ if (c->x86 == 6 && c->x86_model >= 0xf)
+ set_cpu_cap(c, X86_FEATURE_CONSTANT_TSC);
+
#ifdef CONFIG_X86_64
set_cpu_cap(c, X86_FEATURE_SYSENTER32);
#endif
@@ -145,9 +141,8 @@ static void init_centaur(struct cpuinfo_x86 *c)
set_cpu_cap(c, X86_FEATURE_ARCH_PERFMON);
}

- switch (c->x86) {
#ifdef CONFIG_X86_32
- case 5:
+ if (c->x86 == 5) {
switch (c->x86_model) {
case 4:
name = "C6";
@@ -207,12 +202,10 @@ static void init_centaur(struct cpuinfo_x86 *c)
c->x86_cache_size = (cc>>24)+(dd>>24);
}
sprintf(c->x86_model_id, "WinChip %s", name);
- break;
+ }
#endif
- case 6:
+ if (c->x86 == 6)
init_c3(c);
- break;
- }
#ifdef CONFIG_X86_64
set_cpu_cap(c, X86_FEATURE_LFENCE_RDTSC);
#endif