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Diffstat (limited to 'arch/x86/boot/compressed/pgtable_64.c')
-rw-r--r--arch/x86/boot/compressed/pgtable_64.c14
1 files changed, 11 insertions, 3 deletions
diff --git a/arch/x86/boot/compressed/pgtable_64.c b/arch/x86/boot/compressed/pgtable_64.c
index a362fa0b849c..8c5107545251 100644
--- a/arch/x86/boot/compressed/pgtable_64.c
+++ b/arch/x86/boot/compressed/pgtable_64.c
@@ -31,16 +31,23 @@ static char trampoline_save[TRAMPOLINE_32BIT_SIZE];
*/
unsigned long *trampoline_32bit __section(.data);
-struct paging_config paging_prepare(void)
+extern struct boot_params *boot_params;
+int cmdline_find_option_bool(const char *option);
+
+struct paging_config paging_prepare(void *rmode)
{
struct paging_config paging_config = {};
unsigned long bios_start, ebda_start;
+ /* Initialize boot_params. Required for cmdline_find_option_bool(). */
+ boot_params = rmode;
+
/*
* Check if LA57 is desired and supported.
*
- * There are two parts to the check:
+ * There are several parts to the check:
* - if the kernel supports 5-level paging: CONFIG_X86_5LEVEL=y
+ * - if user asked to disable 5-level paging: no5lvl in cmdline
* - if the machine supports 5-level paging:
* + CPUID leaf 7 is supported
* + the leaf has the feature bit set
@@ -48,6 +55,7 @@ struct paging_config paging_prepare(void)
* That's substitute for boot_cpu_has() in early boot code.
*/
if (IS_ENABLED(CONFIG_X86_5LEVEL) &&
+ !cmdline_find_option_bool("no5lvl") &&
native_cpuid_eax(0) >= 7 &&
(native_cpuid_ecx(7) & (1 << (X86_FEATURE_LA57 & 31)))) {
paging_config.l5_required = 1;
@@ -130,7 +138,7 @@ void cleanup_trampoline(void *pgtable)
{
void *trampoline_pgtable;
- trampoline_pgtable = trampoline_32bit + TRAMPOLINE_32BIT_PGTABLE_OFFSET;
+ trampoline_pgtable = trampoline_32bit + TRAMPOLINE_32BIT_PGTABLE_OFFSET / sizeof(unsigned long);
/*
* Move the top level page table out of trampoline memory,