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x86/boot: Defer setup_real_mode() to early_initcall time

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There's no need to run setup_real_mode() as early as we run it.
Defer it to the same early_initcall that sets up the page
permissions for the real mode code.

This should be a code size reduction.  More importantly, it give us
a longer window in which we can allocate the real mode trampoline.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mario Limonciello <mario_limonciello@dell.com>
Cc: Matt Fleming <mfleming@suse.de>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/fd62f0da4f79357695e9bf3e365623736b05f119.1470821230.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Andy Lutomirski 2016-08-10 02:29:15 -07:00 committed by Ingo Molnar
parent 18bc7bd523
commit d0de0f685d
3 changed files with 12 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
arch/x86/include/asm/realmode.h
View File

@ -59,6 +59,5 @@ extern unsigned char secondary_startup_64[];
#endif
void reserve_real_mode(void);
void setup_real_mode(void);
#endif /* _ARCH_X86_REALMODE_H */

2
arch/x86/kernel/setup.c
View File

@ -1141,8 +1141,6 @@ void __init setup_arch(char **cmdline_p)
/* A CPU has %cr4 if and only if it has CPUID. */
mmu_cr4_features = __read_cr4();
setup_real_mode();
memblock_set_current_limit(get_max_mapped());
/*

15
arch/x86/realmode/init.c
View File

@ -30,7 +30,7 @@ void __init reserve_real_mode(void)
base, (unsigned long long)mem, size);
}
void __init setup_real_mode(void)
static void __init setup_real_mode(void)
{
u16 real_mode_seg;
const u32 *rel;
@ -101,7 +101,7 @@ void __init setup_real_mode(void)
* need to mark it executable at do_pre_smp_initcalls() at least,
* thus run it as a early_initcall().
*/
static int __init set_real_mode_permissions(void)
static void __init set_real_mode_permissions(void)
{
unsigned char *base = (unsigned char *) real_mode_header;
size_t size = PAGE_ALIGN(real_mode_blob_end - real_mode_blob);
@ -120,7 +120,16 @@ static int __init set_real_mode_permissions(void)
set_memory_nx((unsigned long) base, size >> PAGE_SHIFT);
set_memory_ro((unsigned long) base, ro_size >> PAGE_SHIFT);
set_memory_x((unsigned long) text_start, text_size >> PAGE_SHIFT);
}
static int __init init_real_mode(void)
{
if (!real_mode_header)
panic("Real mode trampoline was not allocated");
setup_real_mode();
set_real_mode_permissions();
return 0;
}
early_initcall(set_real_mode_permissions);
early_initcall(init_real_mode);