Commit 072a2767 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

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()
parents f6a3308d 527f7214

arch/x86/boot/compressed/efi_thunk_64.S

+21 −9
Original line number Diff line number Diff line
@@ -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)

arch/x86/boot/compressed/head_64.S

+3 −0
Original line number Diff line number Diff line
@@ -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

arch/x86/kernel/cpu/resctrl/monitor.c

+6 −0
Original line number Diff line number Diff line
@@ -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) {