@@ -5,5 +5,8 @@
int cmdline_find_option_bool(const char *cmdline_ptr, const char *option);
int cmdline_find_option(const char *cmdline_ptr, const char *option,
char *buffer, int bufsize);
+int cmdline_find_option_in_range(const char *cmdline_ptr, int cmdline_size,
+ const char *option, char *buffer, int bufsize,
+ char **arg_pos);
#endif /* _ASM_X86_CMDLINE_H */
@@ -243,16 +243,31 @@ static void __init fpu__init_system_ctx_switch(void)
WARN_ON_FPU(current->thread.fpu.initialized);
}
+static void __init clear_cpuid(void)
+{
+ char arg[32], *argptr, *option_pos, clearcpuid_option[] = "clearcpuid";
+ int bit, cmdline_size;
+
+ /* Find each option in boot_command_line and clear specified cpu cap. */
+ cmdline_size = COMMAND_LINE_SIZE;
+ while (cmdline_find_option_in_range(boot_command_line, cmdline_size,
+ clearcpuid_option, arg,
+ sizeof(arg), &option_pos) >= 0) {
+ /* Chang command line range for next search. */
+ cmdline_size = option_pos - boot_command_line + 1;
+ argptr = arg;
+ if (get_option(&argptr, &bit) &&
+ bit >= 0 && bit < NCAPINTS * 32)
+ setup_clear_cpu_cap(bit);
+ }
+}
+
/*
* We parse fpu parameters early because fpu__init_system() is executed
* before parse_early_param().
*/
static void __init fpu__init_parse_early_param(void)
{
- char arg[32];
- char *argptr = arg;
- int bit;
-
if (cmdline_find_option_bool(boot_command_line, "no387"))
setup_clear_cpu_cap(X86_FEATURE_FPU);
@@ -271,12 +286,7 @@ static void __init fpu__init_parse_early_param(void)
if (cmdline_find_option_bool(boot_command_line, "noxsaves"))
setup_clear_cpu_cap(X86_FEATURE_XSAVES);
- if (cmdline_find_option(boot_command_line, "clearcpuid", arg,
- sizeof(arg)) &&
- get_option(&argptr, &bit) &&
- bit >= 0 &&
- bit < NCAPINTS * 32)
- setup_clear_cpu_cap(bit);
+ clear_cpuid();
}
/*
@@ -114,13 +114,15 @@ __cmdline_find_option_bool(const char *cmdline, int max_cmdline_size,
* @option: option string to look for
* @buffer: memory buffer to return the option argument
* @bufsize: size of the supplied memory buffer
+ * @option_pos: pointer to the option if found
*
* Returns the length of the argument (regardless of if it was
* truncated to fit in the buffer), or -1 on not found.
*/
static int
__cmdline_find_option(const char *cmdline, int max_cmdline_size,
- const char *option, char *buffer, int bufsize)
+ const char *option, char *buffer, int bufsize,
+ char **arg_pos)
{
char c;
int pos = 0, len = -1;
@@ -164,6 +166,9 @@ __cmdline_find_option(const char *cmdline, int max_cmdline_size,
len = 0;
bufptr = buffer;
state = st_bufcpy;
+ if (arg_pos)
+ *arg_pos = (char *)cmdline -
+ strlen(option) - 1;
break;
} else if (c == *opptr++) {
/*
@@ -211,5 +216,13 @@ int cmdline_find_option(const char *cmdline, const char *option, char *buffer,
int bufsize)
{
return __cmdline_find_option(cmdline, COMMAND_LINE_SIZE, option,
- buffer, bufsize);
+ buffer, bufsize, NULL);
+}
+
+int cmdline_find_option_in_range(const char *cmdline, int cmdline_size,
+ char *option, char *buffer, int bufsize,
+ char **arg_pos)
+{
+ return __cmdline_find_option(cmdline, cmdline_size, option, buffer,
+ bufsize, arg_pos);
}
Currently only one kernel option "clearcpuid=" can be picked up by kernel during boot time. In some cases, user may want to clear a few cpu caps. This may be useful to replace endless (new) kernel options like nosmep, nosmap, etc. Add support of multiple clearcpuid options to allow user to clear multiple cpu caps. Signed-off-by: Fenghua Yu <fenghua.yu@intel.com> --- arch/x86/include/asm/cmdline.h | 3 +++ arch/x86/kernel/fpu/init.c | 30 ++++++++++++++++++++---------- arch/x86/lib/cmdline.c | 17 +++++++++++++++-- 3 files changed, 38 insertions(+), 12 deletions(-)