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Commit 17d57a9206b4de6ad082ac9f2d2346985abbd2aa

Authored by Eric W. Biederman
Committed by Ingo Molnar
1 parent 0c1b272406

x86: fix x86-32 early fixmap initialization. 

pageexec@freemail.hu writes:

> i've just noticed that the chunk in i386/kernel/head.S ended up in a
> weird place, namely, it's not going to be executed as it's just after
> a 'jmp 3f' and before startup_32_smp, probably not what you intended.
> on a sidenote, the whole thing can be done in a single insn, like:
>
> movl $(swapper_pg_pmd - __PAGE_OFFSET + 0x067), (swapper_pg_dir -
> __PAGE_OFFSET+ 4092)

Thanks for the reminder I thought we had fixed this problem a while ago.

Needed to get fixed virtual address for USB debug and earlycon with mmio.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

Showing 1 changed file with 6 additions and 6 deletions Side-by-side Diff

arch/x86/kernel/head_32.S
Diff comments   View file @ 17d57a9
... ... @@ -193,6 +193,12 @@
193 193 jb 10b
194 194 movl %edi,(init_pg_tables_end - __PAGE_OFFSET)
195 195  
  196 + /* Do an early initialization of the fixmap area */
  197 + movl $(swapper_pg_dir - __PAGE_OFFSET), %edx
  198 + movl $(swapper_pg_pmd - __PAGE_OFFSET), %eax
  199 + addl $0x007, %eax /* 0x007 = PRESENT+RW+USER */
  200 + movl %eax, 4092(%edx)
  201 +
196 202 xorl %ebx,%ebx /* This is the boot CPU (BSP) */
197 203 jmp 3f
198 204 /*
... ... @@ -207,12 +213,6 @@
207 213 #ifndef CONFIG_HOTPLUG_CPU
208 214 .section .init.text,"ax",@progbits
209 215 #endif
210   -
211   - /* Do an early initialization of the fixmap area */
212   - movl $(swapper_pg_dir - __PAGE_OFFSET), %edx
213   - movl $(swapper_pg_pmd - __PAGE_OFFSET), %eax
214   - addl $0x007, %eax /* 0x007 = PRESENT+RW+USER */
215   - movl %eax, 4092(%edx)
216 216  
217 217 #ifdef CONFIG_SMP
218 218 ENTRY(startup_32_smp)