x86: initial fixmap support
PATCH 3/5 x86: initial fixmap support
[PATCH 3/5] x86: initial fixmap support
From: "Eric W. Biederman" <[email protected]>
needed to get fixed virtual address for USB debug port and earlycon with mmio.
Signed-off-by Eric W. Biderman <[email protected]>
Signed-off-by Yinghai Lu <[email protected]>
arch/i386/kernel/head.S +8 -0
@@ -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
arch/x86_64/kernel/head.S +14 -1
@@ -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.