x86/boot/e820: Separate the E820 ABI structures from the in-kernel structures

Linus pointed out that relying on the compiler to pack structures with
enums is fragile not just for the kernel, but for external tooling as
well which might rely on our UAPI headers.

So separate the two from each other: introduce 'struct boot_e820_entry',
which is the boot protocol entry format.

This actually simplifies the code, as e820__update_table() is now never
called directly with boot protocol table entries - we can rely on
append_e820_table() and do a e820__update_table() call afterwards.

( This will allow further simplifications of __e820__update_table(),
  but that will be done in a separate patch. )

This change also has the side effect of not modifying the bootparams structure
anymore - which might be useful for debugging. In theory we could even constify
the boot_params structure - at least from the E820 code's point of view.

Remove the uapi/asm/e820/types.h file, as it's not used anymore - all
kernel side E820 types are defined in asm/e820/types.h.

Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Alex Thorlton <athorlton@sgi.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Huang, Ying <ying.huang@intel.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Paul Jackson <pj@sgi.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

3 files changed, 11 insertions, 11 deletions

diff --git a/arch/x86/boot/compressed/eboot.c b/arch/x86/boot/compressed/eboot.c
index 4cfba2f79dfd..a6099d7c39f6 100644
--- a/arch/x86/boot/compressed/eboot.c
+++ b/arch/x86/boot/compressed/eboot.c
@@ -900,7 +900,7 @@ static void add_e820ext(struct boot_params *params,
 	unsigned long size;
 
 	e820ext->type = SETUP_E820_EXT;
-	e820ext->len = nr_entries * sizeof(struct e820_entry);
+	e820ext->len = nr_entries * sizeof(struct boot_e820_entry);
 	e820ext->next = 0;
 
 	data = (struct setup_data *)(unsigned long)params->hdr.setup_data;
@@ -917,9 +917,9 @@ static void add_e820ext(struct boot_params *params,
 static efi_status_t setup_e820(struct boot_params *params,
 			       struct setup_data *e820ext, u32 e820ext_size)
 {
-	struct e820_entry *e820_table = &params->e820_table[0];
+	struct boot_e820_entry *entry = params->e820_table;
 	struct efi_info *efi = &params->efi_info;
-	struct e820_entry *prev = NULL;
+	struct boot_e820_entry *prev = NULL;
 	u32 nr_entries;
 	u32 nr_desc;
 	int i;
@@ -990,13 +990,13 @@ static efi_status_t setup_e820(struct boot_params *params,
 				return EFI_BUFFER_TOO_SMALL;
 
 			/* boot_params map full, switch to e820 extended */
-			e820_table = (struct e820_entry *)e820ext->data;
+			entry = (struct boot_e820_entry *)e820ext->data;
 		}
 
-		e820_table->addr = d->phys_addr;
-		e820_table->size = d->num_pages << PAGE_SHIFT;
-		e820_table->type = e820_type;
-		prev = e820_table++;
+		entry->addr = d->phys_addr;
+		entry->size = d->num_pages << PAGE_SHIFT;
+		entry->type = e820_type;
+		prev = entry++;
 		nr_entries++;
 	}
 
diff --git a/arch/x86/boot/compressed/kaslr.c b/arch/x86/boot/compressed/kaslr.c
index e8155eab5474..6d9a546ec7ae 100644
--- a/arch/x86/boot/compressed/kaslr.c
+++ b/arch/x86/boot/compressed/kaslr.c
@@ -426,7 +426,7 @@ static unsigned long slots_fetch_random(void)
 	return 0;
 }
 
-static void process_e820_entry(struct e820_entry *entry,
+static void process_e820_entry(struct boot_e820_entry *entry,
 			       unsigned long minimum,
 			       unsigned long image_size)
 {
diff --git a/arch/x86/boot/memory.c b/arch/x86/boot/memory.c
index db62445b75aa..d9c28c87e477 100644
--- a/arch/x86/boot/memory.c
+++ b/arch/x86/boot/memory.c
@@ -21,8 +21,8 @@ static int detect_memory_e820(void)
 {
 	int count = 0;
 	struct biosregs ireg, oreg;
-	struct e820_entry *desc = boot_params.e820_table;
-	static struct e820_entry buf; /* static so it is zeroed */
+	struct boot_e820_entry *desc = boot_params.e820_table;
+	static struct boot_e820_entry buf; /* static so it is zeroed */
 
 	initregs(&ireg);
 	ireg.ax  = 0xe820;