diff options
| author | James Bottomley <James.Bottomley@HansenPartnership.com> | 2011-04-14 18:25:21 -0500 |
|---|---|---|
| committer | James Bottomley <James.Bottomley@suse.de> | 2011-04-15 12:55:18 -0500 |
| commit | d7dd2ff11b7fcd425aca5a875983c862d19a67ae (patch) | |
| tree | 6ad74d89d2355861b513eefb763ea6103a8d68e7 /arch/parisc/kernel | |
| parent | e38f5b745075828ac51b12c8c95c85a7be4a3ec7 (diff) | |
[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 <James.Bottomley@suse.de>
Diffstat (limited to 'arch/parisc/kernel')
| -rw-r--r-- | arch/parisc/kernel/entry.S | 3 | ||||
| -rw-r--r-- | arch/parisc/kernel/head.S | 5 | ||||
| -rw-r--r-- | arch/parisc/kernel/module.c | 10 | ||||
| -rw-r--r-- | arch/parisc/kernel/vmlinux.lds.S | 1 |
4 files changed, 16 insertions, 3 deletions
diff --git a/arch/parisc/kernel/entry.S b/arch/parisc/kernel/entry.S index ead8d2a1034..6f059443914 100644 --- a/arch/parisc/kernel/entry.S +++ b/arch/parisc/kernel/entry.S @@ -692,6 +692,9 @@ ENTRY(fault_vector_11) END(fault_vector_11) #endif + /* Fault vector is separately protected and *must* be on its own page */ + .align PAGE_SIZE +ENTRY(end_fault_vector) .import handle_interruption,code .import do_cpu_irq_mask,code diff --git a/arch/parisc/kernel/head.S b/arch/parisc/kernel/head.S index 145c5e4caaa..37aabd772fb 100644 --- a/arch/parisc/kernel/head.S +++ b/arch/parisc/kernel/head.S @@ -106,8 +106,9 @@ $bss_loop: #endif - /* Now initialize the PTEs themselves */ - ldo 0+_PAGE_KERNEL(%r0),%r3 /* Hardwired 0 phys addr start */ + /* Now initialize the PTEs themselves. We use RWX for + * everything ... it will get remapped correctly later */ + ldo 0+_PAGE_KERNEL_RWX(%r0),%r3 /* Hardwired 0 phys addr start */ ldi (1<<(KERNEL_INITIAL_ORDER-PAGE_SHIFT)),%r11 /* PFN count */ load32 PA(pg0),%r1 diff --git a/arch/parisc/kernel/module.c b/arch/parisc/kernel/module.c index 6e81bb596e5..cedbbb8b18d 100644 --- a/arch/parisc/kernel/module.c +++ b/arch/parisc/kernel/module.c @@ -61,8 +61,10 @@ #include <linux/string.h> #include <linux/kernel.h> #include <linux/bug.h> +#include <linux/mm.h> #include <linux/slab.h> +#include <asm/pgtable.h> #include <asm/unwind.h> #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 diff --git a/arch/parisc/kernel/vmlinux.lds.S b/arch/parisc/kernel/vmlinux.lds.S index 8f1e4efd143..bf6a43a322e 100644 --- a/arch/parisc/kernel/vmlinux.lds.S +++ b/arch/parisc/kernel/vmlinux.lds.S @@ -134,6 +134,7 @@ SECTIONS . = ALIGN(16384); __init_begin = .; INIT_TEXT_SECTION(16384) + . = ALIGN(PAGE_SIZE); INIT_DATA_SECTION(16) /* we have to discard exit text and such at runtime, not link time */ .exit.text : |