[PATCH 3/5] x86: initial fixmap support
From: Eric W. Biderman <[email protected]>
needed to get fixed virtual address for USB debug and earlycon with mmio.
Signed-off-by: Eric W. Biderman <[email protected]>
Signed-off-by: Yinghai Lu <[email protected]>
diff --git a/arch/i386/kernel/head.S b/arch/i386/kernel/head.S
index f74dfc4..8271466 100644
--- a/arch/i386/kernel/head.S
+++ b/arch/i386/kernel/head.S
@@ -168,6 +168,12 @@ page_pde_offset = (__PAGE_OFFSET >> 20);
.section .init.text,"ax",@progbits
#endif
+ /* Do an early initialization of the fixmap area */
+ movl $(swapper_pg_dir - __PAGE_OFFSET), %edx
+ movl $(swapper_pg_pmd - __PAGE_OFFSET), %eax
+ addl $0x007, %eax /* 0x007 = PRESENT+RW+USER */
+ movl %eax, 4092(%edx)
+
#ifdef CONFIG_SMP
ENTRY(startup_32_smp)
cld
@@ -507,6 +513,8 @@ ENTRY(_stext)
.section ".bss.page_aligned","w"
ENTRY(swapper_pg_dir)
.fill 1024,4,0
+ENTRY(swapper_pg_pmd)
+ .fill 1024,4,0
ENTRY(empty_zero_page)
.fill 4096,1,0
diff --git a/arch/x86_64/kernel/head.S b/arch/x86_64/kernel/head.S
index 1fab487..941c84b 100644
--- a/arch/x86_64/kernel/head.S
+++ b/arch/x86_64/kernel/head.S
@@ -73,7 +73,11 @@ startup_64:
addq %rbp, init_level4_pgt + (511*8)(%rip)
addq %rbp, level3_ident_pgt + 0(%rip)
+
addq %rbp, level3_kernel_pgt + (510*8)(%rip)
+ addq %rbp, level3_kernel_pgt + (511*8)(%rip)
+
+ addq %rbp, level2_fixmap_pgt + (506*8)(%rip)
/* Add an Identity mapping if I am above 1G */
leaq _text(%rip), %rdi
@@ -314,7 +318,16 @@ NEXT_PAGE(level3_kernel_pgt)
.fill 510,8,0
/* (2^48-(2*1024*1024*1024)-((2^39)*511))/(2^30) = 510 */
.quad level2_kernel_pgt - __START_KERNEL_map + _KERNPG_TABLE
- .fill 1,8,0
+ .quad level2_fixmap_pgt - __START_KERNEL_map + _PAGE_TABLE
+
+NEXT_PAGE(level2_fixmap_pgt)
+ .fill 506,8,0
+ .quad level1_fixmap_pgt - __START_KERNEL_map + _PAGE_TABLE
+ /* 8MB reserved for vsyscalls + a 2MB hole = 4 + 1 entries */
+ .fill 5,8,0
+
+NEXT_PAGE(level1_fixmap_pgt)
+ .fill 512,8,0
NEXT_PAGE(level2_ident_pgt)
/* Since I easily can, map the first 1G.
-
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