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

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Date:	Sat, 8 Sep 2012 15:06:56 -0700
From:	Josh Triplett <josh@...htriplett.org>
To:	linux-kernel@...r.kernel.org
Cc:	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>,
	"H. Peter Anvin" <hpa@...or.com>, x86@...nel.org,
	Len Brown <lenb@...nel.org>,
	Matt Fleming <matt.fleming@...el.com>,
	Olof Johansson <olof@...om.net>,
	Matthew Garrett <mjg@...hat.com>,
	David Howells <dhowells@...hat.com>,
	Rusty Russell <rusty@...tcorp.com.au>,
	Jim Cromie <jim.cromie@...il.com>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	linux-acpi@...r.kernel.org
Subject: [PATCHv3 2/4] efi: Defer freeing boot services memory until after
 ACPI init

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 <josh@...htriplett.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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