From d7dd2ff11b7fcd425aca5a875983c862d19a67ae Mon Sep 17 00:00:00 2001 From: James Bottomley Date: Thu, 14 Apr 2011 18:25:21 -0500 Subject: [PARISC] only make executable areas executable Currently parisc has the whole kernel marked as RWX, meaning any kernel page at all is eligible to be executed. This can cause a theoretical problem on systems with combined I/D TLB because the act of referencing a page causes a TLB insertion with an executable bit. This TLB entry may be used by the CPU as the basis for speculating the page into the I-Cache. If this speculated page is subsequently used for a user process, there is the possibility we will get a stale I-cache line picked up as the binary executes. As a point of good practise, only mark actual kernel text pages as executable. The same has to be done for init_text pages, but they're converted to data pages (and the I-Cache flushed) when the init memory is released. Signed-off-by: James Bottomley --- arch/parisc/kernel/module.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) (limited to 'arch/parisc/kernel/module.c') diff --git a/arch/parisc/kernel/module.c b/arch/parisc/kernel/module.c index 6e81bb5..cedbbb8 100644 --- a/arch/parisc/kernel/module.c +++ b/arch/parisc/kernel/module.c @@ -61,8 +61,10 @@ #include #include #include +#include #include +#include #include #if 0 @@ -214,7 +216,13 @@ void *module_alloc(unsigned long size) { if (size == 0) return NULL; - return vmalloc(size); + /* using RWX means less protection for modules, but it's + * easier than trying to map the text, data, init_text and + * init_data correctly */ + return __vmalloc_node_range(size, 1, VMALLOC_START, VMALLOC_END, + GFP_KERNEL | __GFP_HIGHMEM, + PAGE_KERNEL_RWX, -1, + __builtin_return_address(0)); } #ifndef CONFIG_64BIT -- cgit v1.1