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authorArd Biesheuvel <ardb@kernel.org>2023-08-07 18:27:13 +0200
committerBorislav Petkov (AMD) <bp@alien8.de>2023-08-07 20:52:32 +0200
commitcb1c9e02b0c13032c3aec325643453ba48e96e17 (patch)
treeeb340ba7015e5ebb407b456ba603965883a4244c /drivers/firmware/efi/libstub/efi-stub-helper.c
parentx86/decompressor: Merge trampoline cleanup with switching code (diff)
downloadlinux-cb1c9e02b0c13032c3aec325643453ba48e96e17.tar.xz
linux-cb1c9e02b0c13032c3aec325643453ba48e96e17.zip
x86/efistub: Perform 4/5 level paging switch from the stub
In preparation for updating the EFI stub boot flow to avoid the bare metal decompressor code altogether, implement the support code for switching between 4 and 5 levels of paging before jumping to the kernel proper. Reuse the newly refactored trampoline that the bare metal decompressor uses, but relies on EFI APIs to allocate 32-bit addressable memory and remap it with the appropriate permissions. Given that the bare metal decompressor will no longer call into the trampoline if the number of paging levels is already set correctly, it is no longer needed to remove NX restrictions from the memory range where this trampoline may end up. Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Link: https://lore.kernel.org/r/20230807162720.545787-17-ardb@kernel.org
Diffstat (limited to 'drivers/firmware/efi/libstub/efi-stub-helper.c')
-rw-r--r--drivers/firmware/efi/libstub/efi-stub-helper.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/firmware/efi/libstub/efi-stub-helper.c b/drivers/firmware/efi/libstub/efi-stub-helper.c
index 732984295295..bfa30625f5d0 100644
--- a/drivers/firmware/efi/libstub/efi-stub-helper.c
+++ b/drivers/firmware/efi/libstub/efi-stub-helper.c
@@ -73,6 +73,8 @@ efi_status_t efi_parse_options(char const *cmdline)
efi_loglevel = CONSOLE_LOGLEVEL_QUIET;
} else if (!strcmp(param, "noinitrd")) {
efi_noinitrd = true;
+ } else if (IS_ENABLED(CONFIG_X86_64) && !strcmp(param, "no5lvl")) {
+ efi_no5lvl = true;
} else if (!strcmp(param, "efi") && val) {
efi_nochunk = parse_option_str(val, "nochunk");
efi_novamap |= parse_option_str(val, "novamap");