[PATCH 09/15] x86/fpu: Remove the 'no387' boot option
From: Ingo Molnar
Date: Fri Apr 25 2025 - 04:45:59 EST
Without math emulation there's no point to this option.
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
Documentation/admin-guide/kernel-parameters.txt | 4 ----
arch/x86/Kconfig | 20 +++++++++-----------
arch/x86/kernel/cpu/common.c | 7 -------
3 files changed, 9 insertions(+), 22 deletions(-)
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index d9fd26b95b34..6d391d76336f 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -4049,10 +4049,6 @@
These settings can be accessed at runtime via
the nmi_watchdog and hardlockup_panic sysctls.
- no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
- emulation library even if a 387 maths coprocessor
- is present.
-
no4lvl [RISCV,EARLY] Disable 4-level and 5-level paging modes.
Forces kernel to use 3-level paging instead.
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index cd9dd10b15d2..137b5ddf1f86 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -2725,18 +2725,16 @@ menuconfig APM
1) make sure that you have enough swap space and that it is
enabled.
2) pass the "idle=poll" option to the kernel
- 3) switch on floating point emulation in the kernel and pass
- the "no387" option to the kernel
- 4) pass the "floppy=nodma" option to the kernel
- 5) pass the "mem=4M" option to the kernel (thereby disabling
+ 3) pass the "floppy=nodma" option to the kernel
+ 4) pass the "mem=4M" option to the kernel (thereby disabling
all but the first 4 MB of RAM)
- 6) make sure that the CPU is not over clocked.
- 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
- 8) disable the cache from your BIOS settings
- 9) install a fan for the video card or exchange video RAM
- 10) install a better fan for the CPU
- 11) exchange RAM chips
- 12) exchange the motherboard.
+ 5) make sure that the CPU is not over clocked.
+ 6) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
+ 7) disable the cache from your BIOS settings
+ 8) install a fan for the video card or exchange video RAM
+ 9) install a better fan for the CPU
+ 10) exchange RAM chips
+ 11) exchange the motherboard.
To compile this driver as a module, choose M here: the
module will be called apm.
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 12126adbc3a9..1755ef511fd7 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -1574,13 +1574,6 @@ static void __init cpu_parse_early_param(void)
int arglen;
#ifdef CONFIG_X86_32
- if (cmdline_find_option_bool(boot_command_line, "no387"))
-#ifdef CONFIG_MATH_EMULATION
- setup_clear_cpu_cap(X86_FEATURE_FPU);
-#else
- pr_err("Option 'no387' required CONFIG_MATH_EMULATION enabled.\n");
-#endif
-
if (cmdline_find_option_bool(boot_command_line, "nofxsr"))
setup_clear_cpu_cap(X86_FEATURE_FXSR);
#endif
--
2.45.2