EFI fixes for v6.10 #3

- Ensure that EFI runtime services are not unmapped by PAN on ARM
 - Avoid freeing the memory holding the EFI memory map inadvertently on
   x86
 - Avoid a false positive kmemleak warning on arm64
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Merge tag 'efi-fixes-for-v6.10-3' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi

Pull EFI fixes from Ard Biesheuvel:
 "Another small set of EFI fixes. Only the x86 one is likely to affect
  any actual users (and has a cc:stable), but the issue it fixes was
  only observed in an unusual context (kexec in a confidential VM).

   - Ensure that EFI runtime services are not unmapped by PAN on ARM

   - Avoid freeing the memory holding the EFI memory map inadvertently
     on x86

   - Avoid a false positive kmemleak warning on arm64"

* tag 'efi-fixes-for-v6.10-3' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi:
  efi/arm64: Fix kmemleak false positive in arm64_efi_rt_init()
  efi/x86: Free EFI memory map only when installing a new one.
  efi/arm: Disable LPAE PAN when calling EFI runtime services

arch/arm/include/asm/efi.h

@@ -14,6 +14,7 @@
 #include <asm/mach/map.h>
 #include <asm/mmu_context.h>
 #include <asm/ptrace.h>
+#include <asm/uaccess.h>
 
 #ifdef CONFIG_EFI
 void efi_init(void);
@@ -25,6 +26,18 @@ int efi_set_mapping_permissions(struct mm_struct *mm, efi_memory_desc_t *md, boo
 #define arch_efi_call_virt_setup()	efi_virtmap_load()
 #define arch_efi_call_virt_teardown()	efi_virtmap_unload()
 
+#ifdef CONFIG_CPU_TTBR0_PAN
+#undef arch_efi_call_virt
+#define arch_efi_call_virt(p, f, args...) ({				\
+	unsigned int flags = uaccess_save_and_enable();			\
+	efi_status_t res = _Generic((p)->f(args),			\
+			efi_status_t:	(p)->f(args),			\
+			default:	((p)->f(args), EFI_ABORTED));	\
+	uaccess_restore(flags);						\
+	res;								\
+})
+#endif
+
 #define ARCH_EFI_IRQ_FLAGS_MASK \
 	(PSR_J_BIT | PSR_E_BIT | PSR_A_BIT | PSR_I_BIT | PSR_F_BIT | \
 	 PSR_T_BIT | MODE_MASK)

arch/arm64/kernel/efi.c

@@ -9,6 +9,7 @@
 
 #include <linux/efi.h>
 #include <linux/init.h>
+#include <linux/kmemleak.h>
 #include <linux/screen_info.h>
 #include <linux/vmalloc.h>
 
@@ -213,6 +214,7 @@ l:	if (!p) {
 		return -ENOMEM;
 	}
 
+	kmemleak_not_leak(p);
 	efi_rt_stack_top = p + THREAD_SIZE;
 	return 0;
 }

arch/x86/include/asm/efi.h

@@ -401,7 +401,6 @@ extern int __init efi_memmap_alloc(unsigned int num_entries,
 				   struct efi_memory_map_data *data);
 extern void __efi_memmap_free(u64 phys, unsigned long size,
 			      unsigned long flags);
-#define __efi_memmap_free __efi_memmap_free
 
 extern int __init efi_memmap_install(struct efi_memory_map_data *data);
 extern int __init efi_memmap_split_count(efi_memory_desc_t *md,

arch/x86/platform/efi/memmap.c

@@ -92,12 +92,22 @@ int __init efi_memmap_alloc(unsigned int num_entries,
  */
 int __init efi_memmap_install(struct efi_memory_map_data *data)
 {
+	unsigned long size = efi.memmap.desc_size * efi.memmap.nr_map;
+	unsigned long flags = efi.memmap.flags;
+	u64 phys = efi.memmap.phys_map;
+	int ret;
+
 	efi_memmap_unmap();
 
 	if (efi_enabled(EFI_PARAVIRT))
 		return 0;
 
-	return __efi_memmap_init(data);
+	ret = __efi_memmap_init(data);
+	if (ret)
+		return ret;
+
+	__efi_memmap_free(phys, size, flags);
+	return 0;
 }
 
 /**

drivers/firmware/efi/memmap.c

@@ -15,10 +15,6 @@
 #include <asm/early_ioremap.h>
 #include <asm/efi.h>
 
-#ifndef __efi_memmap_free
-#define __efi_memmap_free(phys, size, flags) do { } while (0)
-#endif
-
 /**
  * __efi_memmap_init - Common code for mapping the EFI memory map
  * @data: EFI memory map data
@@ -51,11 +47,6 @@ int __init __efi_memmap_init(struct efi_memory_map_data *data)
 		return -ENOMEM;
 	}
 
-	if (efi.memmap.flags & (EFI_MEMMAP_MEMBLOCK | EFI_MEMMAP_SLAB))
-		__efi_memmap_free(efi.memmap.phys_map,
-				  efi.memmap.desc_size * efi.memmap.nr_map,
-				  efi.memmap.flags);
-
 	map.phys_map = data->phys_map;
 	map.nr_map = data->size / data->desc_size;
 	map.map_end = map.map + data->size;