diff options
| author | Linus Torvalds <torvalds@linux-foundation.org> | 2026-04-14 14:50:51 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2026-04-14 14:50:51 -0700 |
| commit | e9635f2a73604ad9cb33d480b489a03bdd03329f (patch) | |
| tree | f7a132b908ab5803d87d2d7382472c11e33f5228 | |
| parent | fabd5a8d24fb5b430f71d3d3608696a7d5e9d720 (diff) | |
| parent | f0958d588e6de263224ca92087b45ce72fa25c91 (diff) | |
Merge tag 'x86_fred_for_v7.1_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 FRED updates from Borislav Petkov:
"We made the FRED support an opt-in initially out of fear of it
breaking machines left and right in the case of a hw bug in the first
generation of machines supporting it.
Now that that the FRED code has seen a lot of hammering, flip the
logic to be opt-out as is the usual case with new hw features"
* tag 'x86_fred_for_v7.1_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/fred: Remove kernel log message when initializing exceptions
x86/fred: Enable FRED by default
| -rw-r--r-- | Documentation/admin-guide/kernel-parameters.txt | 4 | ||||
| -rw-r--r-- | arch/x86/Kconfig | 2 | ||||
| -rw-r--r-- | arch/x86/kernel/cpu/common.c | 2 | ||||
| -rw-r--r-- | arch/x86/kernel/fred.c | 3 |
4 files changed, 4 insertions, 7 deletions
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 291f4da37712..f2ce1f4975c1 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -1765,8 +1765,8 @@ Kernel parameters fred= [X86-64] Enable/disable Flexible Return and Event Delivery. Format: { on | off } - on: enable FRED when it's present. - off: disable FRED, the default setting. + on: enable FRED when it's present, the default setting. + off: disable FRED. ftrace=[tracer] [FTRACE] will set and start the specified tracer diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 733f50956290..0b5f30d769ff 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -554,7 +554,7 @@ config X86_FRED bool "Flexible Return and Event Delivery" depends on X86_64 help - When enabled, try to use Flexible Return and Event Delivery + When enabled, use Flexible Return and Event Delivery instead of the legacy SYSCALL/SYSENTER/IDT architecture for ring transitions and exception/interrupt handling if the system supports it. diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index 8060cccd24d8..4e1f0c4afe3a 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -1761,7 +1761,7 @@ static void __init cpu_parse_early_param(void) /* Minimize the gap between FRED is available and available but disabled. */ arglen = cmdline_find_option(boot_command_line, "fred", arg, sizeof(arg)); - if (arglen != 2 || strncmp(arg, "on", 2)) + if (arglen == 3 && !strncmp(arg, "off", 3)) setup_clear_cpu_cap(X86_FEATURE_FRED); arglen = cmdline_find_option(boot_command_line, "clearcpuid", arg, sizeof(arg)); diff --git a/arch/x86/kernel/fred.c b/arch/x86/kernel/fred.c index e736b19e18de..117aa06d25ca 100644 --- a/arch/x86/kernel/fred.c +++ b/arch/x86/kernel/fred.c @@ -27,9 +27,6 @@ EXPORT_PER_CPU_SYMBOL(fred_rsp0); void cpu_init_fred_exceptions(void) { - /* When FRED is enabled by default, remove this log message */ - pr_info("Initialize FRED on CPU%d\n", smp_processor_id()); - /* * If a kernel event is delivered before a CPU goes to user level for * the first time, its SS is NULL thus NULL is pushed into the SS field |