[PATCHv3 2/4] efi: Defer freeing boot services memory until after ACPI init

[Josh Triplett]

Some new ACPI 5.0 tables reference resources stored in boot services
memory, so keep that memory around until we have ACPI and can extract
data from it.

Signed-off-by: Josh Triplett <j...@joshtriplett.org>
---
 arch/x86/platform/efi/efi.c |   31 ++++++++++++++++++-------------
 include/linux/efi.h         |    2 ++
 init/main.c                 |    3 +++
 3 files changed, 23 insertions(+), 13 deletions(-)

diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
index 92660eda..ab2cfe8 100644
--- a/arch/x86/platform/efi/efi.c
+++ b/arch/x86/platform/efi/efi.c
@@ -419,10 +419,21 @@ void __init efi_reserve_boot_services(void)
        }
 }
 
-static void __init efi_free_boot_services(void)
+static void __init efi_unmap_memmap(void)
+{
+       if (memmap.map) {
+               early_iounmap(memmap.map, memmap.nr_map * memmap.desc_size);
+               memmap.map = NULL;
+       }
+}
+
+void __init efi_free_boot_services(void)
 {
        void *p;
 
+       if (!efi_native)
+               return;
+
        for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
                efi_memory_desc_t *md = p;
                unsigned long long start = md->phys_addr;
@@ -438,6 +449,8 @@ static void __init efi_free_boot_services(void)
 
                free_bootmem_late(start, size);
        }
+
+       efi_unmap_memmap();
 }
 
 static int __init efi_systab_init(void *phys)
@@ -787,8 +800,10 @@ void __init efi_enter_virtual_mode(void)
         * non-native EFI
         */
 
-       if (!efi_native)
-               goto out;
+       if (!efi_native) {
+               efi_unmap_memmap();
+               return;
+       }
 
        /* Merge contiguous regions of the same type and attribute */
        for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
@@ -878,13 +893,6 @@ void __init efi_enter_virtual_mode(void)
        }
 
        /*
-        * Thankfully, it does seem that no runtime services other than
-        * SetVirtualAddressMap() will touch boot services code, so we can
-        * get rid of it all at this point
-        */
-       efi_free_boot_services();
-
-       /*
         * Now that EFI is in virtual mode, update the function
         * pointers in the runtime service table to the new virtual addresses.
         *
@@ -906,9 +914,6 @@ void __init efi_enter_virtual_mode(void)
        if (__supported_pte_mask & _PAGE_NX)
                runtime_code_page_mkexec();
 
-out:
-       early_iounmap(memmap.map, memmap.nr_map * memmap.desc_size);
-       memmap.map = NULL;
        kfree(new_memmap);
 }
 
diff --git a/include/linux/efi.h b/include/linux/efi.h
index 52fbedf..3c72c27 100644
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -497,8 +497,10 @@ extern void efi_memmap_walk (efi_freemem_callback_t 
callback, void *arg);
 extern void efi_gettimeofday (struct timespec *ts);
 #ifdef CONFIG_X86
 extern void efi_enter_virtual_mode (void);     /* switch EFI to virtual mode, 
if possible */
+extern void efi_free_boot_services(void);
 #else
 static void efi_enter_virtual_mode(void) {}
+static void efi_free_boot_services(void) {}
 #endif
 extern u64 efi_get_iobase (void);
 extern u32 efi_mem_type (unsigned long phys_addr);
diff --git a/init/main.c b/init/main.c
index ebb1ba5..78e5491 100644
--- a/init/main.c
+++ b/init/main.c
@@ -629,6 +629,9 @@ asmlinkage void __init start_kernel(void)
        acpi_early_init(); /* before LAPIC and SMP init */
        sfi_init_late();
 
+       if (efi_enabled)
+               efi_free_boot_services();
+
        ftrace_init();
 
        /* Do the rest non-__init'ed, we're now alive */
-- 
1.7.10.4

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