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authorMichael Roth <michael.roth@amd.com>2022-07-06 05:53:15 +0300
committerBorislav Petkov <bp@suse.de>2022-07-06 12:23:39 +0300
commitb57feed2cc2622ae14b2fa62f19e973e5e0a60cf (patch)
treeec9328cb876bbe1ae169bc06fa4babe952946be6 /arch
parent7e09ac27f43b382f5fe9bb7c7f4c465ece1f8a23 (diff)
downloadlinux-b57feed2cc2622ae14b2fa62f19e973e5e0a60cf.tar.xz
x86/compressed/64: Add identity mappings for setup_data entries
The decompressed kernel initially relies on the identity map set up by the boot/compressed kernel for accessing things like boot_params. With the recent introduction of SEV-SNP support, the decompressed kernel also needs to access the setup_data entries pointed to by boot_params->hdr.setup_data. This can lead to a crash in the kexec kernel during early boot due to these entries not currently being included in the initial identity map, see thread at Link below. Include mappings for the setup_data entries in the initial identity map. [ bp: Massage commit message and use a helper var for better readability. ] Fixes: b190a043c49a ("x86/sev: Add SEV-SNP feature detection/setup") Reported-by: Jun'ichi Nomura <junichi.nomura@nec.com> Signed-off-by: Michael Roth <michael.roth@amd.com> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lore.kernel.org/r/TYCPR01MB694815CD815E98945F63C99183B49@TYCPR01MB6948.jpnprd01.prod.outlook.com
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/boot/compressed/ident_map_64.c13
1 files changed, 13 insertions, 0 deletions
diff --git a/arch/x86/boot/compressed/ident_map_64.c b/arch/x86/boot/compressed/ident_map_64.c
index 44c350d627c7..d4a314cc50d6 100644
--- a/arch/x86/boot/compressed/ident_map_64.c
+++ b/arch/x86/boot/compressed/ident_map_64.c
@@ -110,6 +110,7 @@ void kernel_add_identity_map(unsigned long start, unsigned long end)
void initialize_identity_maps(void *rmode)
{
unsigned long cmdline;
+ struct setup_data *sd;
/* Exclude the encryption mask from __PHYSICAL_MASK */
physical_mask &= ~sme_me_mask;
@@ -163,6 +164,18 @@ void initialize_identity_maps(void *rmode)
cmdline = get_cmd_line_ptr();
kernel_add_identity_map(cmdline, cmdline + COMMAND_LINE_SIZE);
+ /*
+ * Also map the setup_data entries passed via boot_params in case they
+ * need to be accessed by uncompressed kernel via the identity mapping.
+ */
+ sd = (struct setup_data *)boot_params->hdr.setup_data;
+ while (sd) {
+ unsigned long sd_addr = (unsigned long)sd;
+
+ kernel_add_identity_map(sd_addr, sd_addr + sizeof(*sd) + sd->len);
+ sd = (struct setup_data *)sd->next;
+ }
+
sev_prep_identity_maps(top_level_pgt);
/* Load the new page-table. */