From 38cb47ba0187c481aa949d3bbf149e014e8cacda Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Mon, 4 Feb 2008 16:47:54 +0100 Subject: [PATCH] x86: relax RAM check in ioremap() Kevin Winchester reported the loss of direct rendering, due to: [ 0.588184] agpgart: Detected AGP bridge 0 [ 0.588184] agpgart: unable to get memory for graphics translation table. [ 0.588184] agpgart: agp_backend_initialize() failed. [ 0.588207] agpgart-amd64: probe of 0000:00:00.0 failed with error -12 and bisected it down to: commit 266b9f8727976769e2ed2dad77ac9295f37e321e Author: Thomas Gleixner Date: Wed Jan 30 13:34:06 2008 +0100 x86: fix ioremap RAM check this check was too strict and caused an ioremap() failure. the problem is due to the somewhat unclean way of how the GART code reserves a memory range for its aperture, and how it utilizes it later on. Allow RAM pages to be ioremap()-ed too, as long as they are reserved. Bisected-by: Kevin Winchester Signed-off-by: Ingo Molnar Tested-by: Kevin Winchester Signed-off-by: Thomas Gleixner --- arch/x86/mm/ioremap.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c index c004d94608fd..1a88d1572a77 100644 --- a/arch/x86/mm/ioremap.c +++ b/arch/x86/mm/ioremap.c @@ -116,7 +116,7 @@ static void __iomem *__ioremap(unsigned long phys_addr, unsigned long size, { void __iomem *addr; struct vm_struct *area; - unsigned long offset, last_addr; + unsigned long pfn, offset, last_addr; pgprot_t prot; /* Don't allow wraparound or zero size */ @@ -133,9 +133,10 @@ static void __iomem *__ioremap(unsigned long phys_addr, unsigned long size, /* * Don't allow anybody to remap normal RAM that we're using.. */ - for (offset = phys_addr >> PAGE_SHIFT; offset < max_pfn_mapped && - (offset << PAGE_SHIFT) < last_addr; offset++) { - if (page_is_ram(offset)) + for (pfn = phys_addr >> PAGE_SHIFT; pfn < max_pfn_mapped && + (pfn << PAGE_SHIFT) < last_addr; pfn++) { + if (page_is_ram(pfn) && pfn_valid(pfn) && + !PageReserved(pfn_to_page(pfn))) return NULL; } -- 2.11.0