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authorLinus Torvalds <torvalds@linux-foundation.org>2021-08-29 10:26:00 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2021-08-29 10:26:00 -0700
commit072a276745da10620c9b84a08519620670ba7496 (patch)
treee0118d29a40a6a0352c348a61a8c0b9ee0855fb5
parentf6a3308d6feb351d9854eb8b3f6289a1ac163125 (diff)
parent527f721478bce3f49b513a733bacd19d6f34b08c (diff)
Merge tag 'x86_urgent_for_v5.14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fixes from Borislav Petkov: - Fix build error on RHEL where -Werror=maybe-uninitialized is set. - Restore the firmware's IDT when calling EFI boot services and before ExitBootServices() has been called. This fixes a boot failure on what appears to be a tablet with 32-bit UEFI running a 64-bit kernel. * tag 'x86_urgent_for_v5.14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/resctrl: Fix a maybe-uninitialized build warning treated as error x86/efi: Restore Firmware IDT before calling ExitBootServices()
-rw-r--r--arch/x86/boot/compressed/efi_thunk_64.S30
-rw-r--r--arch/x86/boot/compressed/head_64.S3
-rw-r--r--arch/x86/kernel/cpu/resctrl/monitor.c6
3 files changed, 30 insertions, 9 deletions
diff --git a/arch/x86/boot/compressed/efi_thunk_64.S b/arch/x86/boot/compressed/efi_thunk_64.S
index 95a223b3e56a..8bb92e9f4e97 100644
--- a/arch/x86/boot/compressed/efi_thunk_64.S
+++ b/arch/x86/boot/compressed/efi_thunk_64.S
@@ -5,9 +5,8 @@
* Early support for invoking 32-bit EFI services from a 64-bit kernel.
*
* Because this thunking occurs before ExitBootServices() we have to
- * restore the firmware's 32-bit GDT before we make EFI service calls,
- * since the firmware's 32-bit IDT is still currently installed and it
- * needs to be able to service interrupts.
+ * restore the firmware's 32-bit GDT and IDT before we make EFI service
+ * calls.
*
* On the plus side, we don't have to worry about mangling 64-bit
* addresses into 32-bits because we're executing with an identity
@@ -39,7 +38,7 @@ SYM_FUNC_START(__efi64_thunk)
/*
* Convert x86-64 ABI params to i386 ABI
*/
- subq $32, %rsp
+ subq $64, %rsp
movl %esi, 0x0(%rsp)
movl %edx, 0x4(%rsp)
movl %ecx, 0x8(%rsp)
@@ -49,14 +48,19 @@ SYM_FUNC_START(__efi64_thunk)
leaq 0x14(%rsp), %rbx
sgdt (%rbx)
+ addq $16, %rbx
+ sidt (%rbx)
+
/*
- * Switch to gdt with 32-bit segments. This is the firmware GDT
- * that was installed when the kernel started executing. This
- * pointer was saved at the EFI stub entry point in head_64.S.
+ * Switch to IDT and GDT with 32-bit segments. This is the firmware GDT
+ * and IDT that was installed when the kernel started executing. The
+ * pointers were saved at the EFI stub entry point in head_64.S.
*
* Pass the saved DS selector to the 32-bit code, and use far return to
* restore the saved CS selector.
*/
+ leaq efi32_boot_idt(%rip), %rax
+ lidt (%rax)
leaq efi32_boot_gdt(%rip), %rax
lgdt (%rax)
@@ -67,7 +71,7 @@ SYM_FUNC_START(__efi64_thunk)
pushq %rax
lretq
-1: addq $32, %rsp
+1: addq $64, %rsp
movq %rdi, %rax
pop %rbx
@@ -128,10 +132,13 @@ SYM_FUNC_START_LOCAL(efi_enter32)
/*
* Some firmware will return with interrupts enabled. Be sure to
- * disable them before we switch GDTs.
+ * disable them before we switch GDTs and IDTs.
*/
cli
+ lidtl (%ebx)
+ subl $16, %ebx
+
lgdtl (%ebx)
movl %cr4, %eax
@@ -166,6 +173,11 @@ SYM_DATA_START(efi32_boot_gdt)
.quad 0
SYM_DATA_END(efi32_boot_gdt)
+SYM_DATA_START(efi32_boot_idt)
+ .word 0
+ .quad 0
+SYM_DATA_END(efi32_boot_idt)
+
SYM_DATA_START(efi32_boot_cs)
.word 0
SYM_DATA_END(efi32_boot_cs)
diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S
index a2347ded77ea..572c535cf45b 100644
--- a/arch/x86/boot/compressed/head_64.S
+++ b/arch/x86/boot/compressed/head_64.S
@@ -319,6 +319,9 @@ SYM_INNER_LABEL(efi32_pe_stub_entry, SYM_L_LOCAL)
movw %cs, rva(efi32_boot_cs)(%ebp)
movw %ds, rva(efi32_boot_ds)(%ebp)
+ /* Store firmware IDT descriptor */
+ sidtl rva(efi32_boot_idt)(%ebp)
+
/* Disable paging */
movl %cr0, %eax
btrl $X86_CR0_PG_BIT, %eax
diff --git a/arch/x86/kernel/cpu/resctrl/monitor.c b/arch/x86/kernel/cpu/resctrl/monitor.c
index 57e4bb695ff9..8caf871b796f 100644
--- a/arch/x86/kernel/cpu/resctrl/monitor.c
+++ b/arch/x86/kernel/cpu/resctrl/monitor.c
@@ -304,6 +304,12 @@ static u64 __mon_event_count(u32 rmid, struct rmid_read *rr)
case QOS_L3_MBM_LOCAL_EVENT_ID:
m = &rr->d->mbm_local[rmid];
break;
+ default:
+ /*
+ * Code would never reach here because an invalid
+ * event id would fail the __rmid_read.
+ */
+ return RMID_VAL_ERROR;
}
if (rr->first) {

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