The following commit has been merged into the x86/core branch of tip:
Commit-ID: f3d7eab7be871d948d896e7021038b092ece687e
Gitweb: https://git.kernel.org/tip/f3d7eab7be871d948d896e7021038b092ece687e
Author: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
AuthorDate: Thu, 29 Feb 2024 15:23:40 +01:00
Committer: Borislav Petkov (AMD) <bp@xxxxxxxxx>
CommitterDate: Mon, 04 Mar 2024 17:39:24 +01:00
x86/idle: Cleanup idle_setup()
Updating the static call for x86_idle() from idle_setup() is
counter-intuitive.
Let select_idle_routine() handle it like the other idle choices, which
allows to simplify the idle selection later on.
While at it rewrite comments and return a proper error code and not -1.
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Borislav Petkov (AMD) <bp@xxxxxxxxx>
Link: https://lore.kernel.org/r/20240229142248.455616019@xxxxxxxxxxxxx
---
arch/x86/kernel/process.c | 24 +++++++-----------------
1 file changed, 7 insertions(+), 17 deletions(-)
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index 792394b..9709959 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -857,8 +857,8 @@ static int prefer_mwait_c1_over_halt(const struct cpuinfo_x86 *c)
{
u32 eax, ebx, ecx, edx;
- /* User has disallowed the use of MWAIT. Fallback to HALT */
- if (boot_option_idle_override == IDLE_NOMWAIT)
+ /* If override is enforced on the command line, fall back to HALT. */
+ if (boot_option_idle_override != IDLE_NO_OVERRIDE)
return 0;
/* MWAIT is not supported on this platform. Fallback to HALT */
@@ -976,24 +976,14 @@ static int __init idle_setup(char *str)
boot_option_idle_override = IDLE_POLL;
cpu_idle_poll_ctrl(true);
} else if (!strcmp(str, "halt")) {
- /*
- * When the boot option of idle=halt is added, halt is
- * forced to be used for CPU idle. In such case CPU C2/C3
- * won't be used again.
- * To continue to load the CPU idle driver, don't touch
- * the boot_option_idle_override.
- */
- static_call_update(x86_idle, default_idle);
+ /* 'idle=halt' HALT for idle. C-states are disabled. */
boot_option_idle_override = IDLE_HALT;
} else if (!strcmp(str, "nomwait")) {
- /*
- * If the boot option of "idle=nomwait" is added,
- * it means that mwait will be disabled for CPU C1/C2/C3
- * states.
- */
+ /* 'idle=nomwait' disables MWAIT for idle */
boot_option_idle_override = IDLE_NOMWAIT;
- } else
- return -1;
+ } else {
+ return -EINVAL;
+ }
return 0;
}
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