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247055aa21
This patch removes the domain switching functionality via the set_fs and __switch_to functions on cores that have a TLS register. Currently, the ioremap and vmalloc areas share the same level 1 page tables and therefore have the same domain (DOMAIN_KERNEL). When the kernel domain is modified from Client to Manager (via the __set_fs or in the __switch_to function), the XN (eXecute Never) bit is overridden and newer CPUs can speculatively prefetch the ioremap'ed memory. Linux performs the kernel domain switching to allow user-specific functions (copy_to/from_user, get/put_user etc.) to access kernel memory. In order for these functions to work with the kernel domain set to Client, the patch modifies the LDRT/STRT and related instructions to the LDR/STR ones. The user pages access rights are also modified for kernel read-only access rather than read/write so that the copy-on-write mechanism still works. CPU_USE_DOMAINS gets disabled only if the hardware has a TLS register (CPU_32v6K is defined) since writing the TLS value to the high vectors page isn't possible. The user addresses passed to the kernel are checked by the access_ok() function so that they do not point to the kernel space. Tested-by: Anton Vorontsov <cbouatmailru@gmail.com> Cc: Tony Lindgren <tony@atomide.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> |
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| .. | ||
| ashldi3.S | ||
| ashrdi3.S | ||
| backtrace.S | ||
| bitops.h | ||
| changebit.S | ||
| clear_user.S | ||
| clearbit.S | ||
| copy_from_user.S | ||
| copy_page.S | ||
| copy_template.S | ||
| copy_to_user.S | ||
| csumipv6.S | ||
| csumpartial.S | ||
| csumpartialcopy.S | ||
| csumpartialcopygeneric.S | ||
| csumpartialcopyuser.S | ||
| delay.S | ||
| div64.S | ||
| ecard.S | ||
| findbit.S | ||
| floppydma.S | ||
| getuser.S | ||
| io-acorn.S | ||
| io-readsb.S | ||
| io-readsl.S | ||
| io-readsw-armv3.S | ||
| io-readsw-armv4.S | ||
| io-shark.c | ||
| io-writesb.S | ||
| io-writesl.S | ||
| io-writesw-armv3.S | ||
| io-writesw-armv4.S | ||
| lib1funcs.S | ||
| lshrdi3.S | ||
| Makefile | ||
| memchr.S | ||
| memcpy.S | ||
| memmove.S | ||
| memset.S | ||
| memzero.S | ||
| muldi3.S | ||
| putuser.S | ||
| setbit.S | ||
| sha1.S | ||
| strchr.S | ||
| strncpy_from_user.S | ||
| strnlen_user.S | ||
| strrchr.S | ||
| testchangebit.S | ||
| testclearbit.S | ||
| testsetbit.S | ||
| uaccess_with_memcpy.c | ||
| uaccess.S | ||
| ucmpdi2.S | ||