From 22def7681186f65f4f1256ae9b0b6db2a7720cb1 Mon Sep 17 00:00:00 2001 From: Max Filippov Date: Tue, 15 Jul 2014 02:27:50 +0400 Subject: xtensa: make fixmap region addressing grow with index It's much easier to reason about alignment and coloring of regions located in the fixmap when fixmap index is just a PFN within the fixmap region. Change fixmap addressing so that index 0 corresponds to FIXADDR_START instead of the FIXADDR_TOP. Signed-off-by: Max Filippov --- arch/xtensa/include/asm/fixmap.h | 27 ++++++++++++++++++++++++--- 1 file changed, 24 insertions(+), 3 deletions(-) (limited to 'arch/xtensa/include/asm') diff --git a/arch/xtensa/include/asm/fixmap.h b/arch/xtensa/include/asm/fixmap.h index 9f6c33d0428a..a43cd5265556 100644 --- a/arch/xtensa/include/asm/fixmap.h +++ b/arch/xtensa/include/asm/fixmap.h @@ -23,8 +23,8 @@ * Here we define all the compile-time 'special' virtual * addresses. The point is to have a constant address at * compile time, but to set the physical address only - * in the boot process. We allocate these special addresses - * from the end of the consistent memory region backwards. + * in the boot process. We allocate these special addresses + * from the start of the consistent memory region upwards. * Also this lets us do fail-safe vmalloc(), we * can guarantee that these special addresses and * vmalloc()-ed addresses never overlap. @@ -47,7 +47,28 @@ enum fixed_addresses { #define FIXADDR_SIZE (__end_of_fixed_addresses << PAGE_SHIFT) #define FIXADDR_START ((FIXADDR_TOP - FIXADDR_SIZE) & PMD_MASK) -#include +#define __fix_to_virt(x) (FIXADDR_START + ((x) << PAGE_SHIFT)) +#define __virt_to_fix(x) (((x) - FIXADDR_START) >> PAGE_SHIFT) + +#ifndef __ASSEMBLY__ +/* + * 'index to address' translation. If anyone tries to use the idx + * directly without translation, we catch the bug with a NULL-deference + * kernel oops. Illegal ranges of incoming indices are caught too. + */ +static __always_inline unsigned long fix_to_virt(const unsigned int idx) +{ + BUILD_BUG_ON(idx >= __end_of_fixed_addresses); + return __fix_to_virt(idx); +} + +static inline unsigned long virt_to_fix(const unsigned long vaddr) +{ + BUG_ON(vaddr >= FIXADDR_TOP || vaddr < FIXADDR_START); + return __virt_to_fix(vaddr); +} + +#endif #define kmap_get_fixmap_pte(vaddr) \ pte_offset_kernel( \ -- cgit v1.2.3-55-g7522