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x86: change static allocation of trampoline area

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Impact: fix trampoline sizing bug, save space

While debugging a suspend-to-RAM related issue it occured to me that
if the trampoline code had grown past 4 KB, we would have been
allocating too little memory for it, since the 4 KB size of the
trampoline is hardcoded into arch/x86/kernel/e820.c .  Change that
by making the kernel compute the trampoline size and allocate as much
memory as necessary.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Rafael J. Wysocki
2008-12-08 00:50:22 +01:00
committed by Ingo Molnar
parent 218d11a8b0
commit 3e1e9002aa
5 changed files with 30 additions and 18 deletions
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19
arch/x86/kernel/trampoline.c
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@@ -1,10 +1,26 @@
#include <linux/io.h>
#include <asm/trampoline.h>
#include <asm/e820.h>
/* ready for x86_64 and x86 */
unsigned char *trampoline_base = __va(TRAMPOLINE_BASE);
void __init reserve_trampoline_memory(void)
{
#ifdef CONFIG_X86_32
/*
* But first pinch a few for the stack/trampoline stuff
* FIXME: Don't need the extra page at 4K, but need to fix
* trampoline before removing it. (see the GDT stuff)
*/
reserve_early(PAGE_SIZE, PAGE_SIZE + PAGE_SIZE, "EX TRAMPOLINE");
#endif
/* Has to be in very low memory so we can execute real-mode AP code. */
reserve_early(TRAMPOLINE_BASE, TRAMPOLINE_BASE + TRAMPOLINE_SIZE,
"TRAMPOLINE");
}
/*
* Currently trivial. Write the real->protected mode
* bootstrap into the page concerned. The caller
@@ -12,7 +28,6 @@ unsigned char *trampoline_base = __va(TRAMPOLINE_BASE);
*/
unsigned long setup_trampoline(void)
{
memcpy(trampoline_base, trampoline_data,
trampoline_end - trampoline_data);
memcpy(trampoline_base, trampoline_data, TRAMPOLINE_SIZE);
return virt_to_phys(trampoline_base);
}