Re: [PATCH 2/5] efi: add kernel param efi=noruntime

From: Dave Young
Date: Wed Aug 13 2014 - 04:15:17 EST


On 08/12/14 at 02:10pm, Dave Young wrote:
> noefi kernel param means actually disabling efi runtime, Per suggestion from
> Leif Lindholm efi=noruntime should be better. But since noefi is already used
> in X86 thus just adding another param efi=noruntime for same purpose.
>
> Signed-off-by: Dave Young <dyoung@xxxxxxxxxx>
> ---
> Documentation/kernel-parameters.txt | 4 +++-
> arch/x86/platform/efi/efi.c | 12 ------------
> drivers/firmware/efi/efi.c | 22 ++++++++++++++++++++++
> 3 files changed, 25 insertions(+), 13 deletions(-)
>
> diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
> index a8eb6af..09d8c54 100644
> --- a/Documentation/kernel-parameters.txt
> +++ b/Documentation/kernel-parameters.txt
> @@ -992,11 +992,13 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
> Format: {"off" | "on" | "skip[mbr]"}
>
> efi= [EFI]
> - Format: { "old_map" }
> + Format: { "old_map" | "noruntime" }
> old_map [X86-64]: switch to the old ioremap-based EFI
> runtime services mapping. 32-bit still uses this one by
> default.
>
> + noruntime : disable EFI runtime services support
> +
> efi_no_storage_paranoia [EFI; X86]
> Using this parameter you can use more than 50% of
> your efi variable storage. Use this parameter only if
> diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
> index dd7aaa1..eae91be 100644
> --- a/arch/x86/platform/efi/efi.c
> +++ b/arch/x86/platform/efi/efi.c
> @@ -929,15 +929,3 @@ u64 efi_mem_attributes(unsigned long phys_addr)
> }
> return 0;
> }
> -
> -static int __init parse_efi_cmdline(char *str)
> -{
> - if (*str == '=')
> - str++;
> -
> - if (!strncmp(str, "old_map", 7))
> - set_bit(EFI_OLD_MEMMAP, &efi.flags);
> -
> - return 0;
> -}
> -early_param("efi", parse_efi_cmdline);
> diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
> index c8f01a7..f3ec3f2 100644
> --- a/drivers/firmware/efi/efi.c
> +++ b/drivers/firmware/efi/efi.c
> @@ -24,6 +24,7 @@
> #include <linux/of_fdt.h>
> #include <linux/io.h>
> #include <linux/platform_device.h>
> +#include <asm/efi.h>
>
> struct efi __read_mostly efi = {
> .mps = EFI_INVALID_TABLE_ADDR,
> @@ -54,6 +55,27 @@ bool efi_runtime_disabled(void)
> return disable_runtime;
> }
>
> +static int __init parse_efi_cmdline(char *str)
> +{
> + if (*str == '=')
> + str++;
> +
> +#ifdef CONFIG_X86
> + if (!strncmp(str, "old_map", 7)) {
> + set_bit(EFI_OLD_MEMMAP, &efi.flags);
> + goto out;
> + }
> +#endif
> + if (!strncmp(str, "noruntime", 9)) {
> + disable_runtime = true;
> + goto out;
> + }
> +

For sharing functions I moved old_map here, but rethinking about it maybe
it's better to keep it in arch code.

Matt, I see you have some code for libstub option parsing, I will rebase
on your efi/next and I'm thinking to add a generic function for parsing
params like below (for old_map, but libstub can not use it):

diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
index c90d3cd..c73a7df5 100644
--- a/arch/x86/platform/efi/efi.c
+++ b/arch/x86/platform/efi/efi.c
@@ -932,26 +932,8 @@ u64 efi_mem_attributes(unsigned long phys_addr)

static int __init parse_efi_cmdline(char *str)
{
- if (*str == '=')
- str++;
-
- while (*str) {
- if (!strncmp(str, "old_map", 7)) {
- set_bit(EFI_OLD_MEMMAP, &efi.flags);
- str += strlen("old_map");
- }
-
- /*
- * Skip any options we don't understand. Presumably
- * they apply to the EFI boot stub.
- */
- while (*str && *str != ',')
- str++;
-
- /* If we hit a delimiter, skip it */
- if (*str == ',')
- str++;
- }
+ if (parse_option_str(str, "old_map"))
+ set_bit(EFI_OLD_MEMMAP, &efi.flags);

return 0;
}
diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index 4c52907..d612718 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -407,6 +407,7 @@ int vsscanf(const char *, const char *, va_list);
extern int get_option(char **str, int *pint);
extern char *get_options(const char *str, int nints, int *ints);
extern unsigned long long memparse(const char *ptr, char **retptr);
+extern bool parse_option_str(const char *str, const char *option);

extern int core_kernel_text(unsigned long addr);
extern int core_kernel_data(unsigned long addr);
diff --git a/lib/cmdline.c b/lib/cmdline.c
index d4932f7..f384125 100644
--- a/lib/cmdline.c
+++ b/lib/cmdline.c
@@ -155,3 +155,32 @@ unsigned long long memparse(const char *ptr, char **retptr)
return ret;
}
EXPORT_SYMBOL(memparse);
+
+/**
+ * parse_option_str - Parse a string and check an option is set or not
+ * @str: String to be parsed
+ * @option: the option name
+ *
+ * This function parses a string containing a comma-separated
+ * list of strings like a=b,c.
+ *
+ * Return true if there's such option in the string, or return false.
+ */
++bool parse_option_str(const char *str, const char *option)
+{
+ while (*str) {
+ if (!strncmp(str, option, strlen(option))) {
+ str += strlen(option);
+ if (!*str || *str == ',')
+ return true;
+ }
+
+ while (*str && *str != ',')
+ str++;
+
+ if (*str == ',')
+ str++;
+ }
+
+ return false;
+}
--
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