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* ARM: 8573/1: domain: move {set,get}_domain under config guardVladimir Murzin2016-05-051-0/+11
| | | | | | | | | | | | | Recursive undefined instrcution falut is seen with R-class taking an exception. The reson for that is __show_regs() tries to get domain information, but domains is not available on !MMU cores, like R/M class. Fix it by puting {set,get}_domain functions under CONFIG_CPU_CP15_MMU guard and providing stubs for the case where domains is not supported. Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
* ARM: domains: add memory dependencies to get_domain/set_domainRussell King2015-09-111-2/+4
| | | | | | | | | | | | | | | | | | | We need to have memory dependencies on get_domain/set_domain to avoid the compiler over-optimising these inline assembly instructions. Loads/stores must not be reordered across a set_domain(), so introduce a compiler barrier for that assembly. The value of get_domain() must not be cached across a set_domain(), but we still want to allow the compiler to optimise it away. Introduce a dependency on current_thread_info()->cpu_domain to avoid this; the new memory clobber in set_domain() should therefore cause the compiler to re-load this. The other advantage of using this is we should have its address in the register set already, or very soon after at most call sites. Tested-by: Robert Jarzmik <robert.jarzmik@free.fr> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
* ARM: software-based priviledged-no-access supportRussell King2015-08-261-2/+19
| | | | | | | | | | | | | | | | | | | | | | | Provide a software-based implementation of the priviledged no access support found in ARMv8.1. Userspace pages are mapped using a different domain number from the kernel and IO mappings. If we switch the user domain to "no access" when we enter the kernel, we can prevent the kernel from touching userspace. However, the kernel needs to be able to access userspace via the various user accessor functions. With the wrapping in the previous patch, we can temporarily enable access when the kernel needs user access, and re-disable it afterwards. This allows us to trap non-intended accesses to userspace, eg, caused by an inadvertent dereference of the LIST_POISON* values, which, with appropriate user mappings setup, can be made to succeed. This in turn can allow use-after-free bugs to be further exploited than would otherwise be possible. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
* ARM: domains: remove DOMAIN_TABLERussell King2015-08-211-3/+0
| | | | | | | DOMAIN_TABLE is not used; in any case, it aliases to the kernel domain. Remove this definition. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
* ARM: domains: keep vectors in separate domainRussell King2015-08-211-1/+3
| | | | | | | | Keep the machine vectors in its own domain to avoid software based user access control from making the vector code inaccessible, and thereby deadlocking the machine. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
* ARM: domains: get rid of manager mode for user domainRussell King2015-08-211-1/+1
| | | | | | | | | Since we switched to early trap initialisation in 94e5a85b3be0 ("ARM: earlier initialization of vectors page") we haven't been writing directly to the vectors page, and so there's no need for this domain to be in manager mode. Switch it to client mode. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
* ARM: domains: move initial domain setting value to asm/domains.hRussell King2015-08-211-0/+6
| | | | Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
* ARM: domains: provide domain_mask()Russell King2015-08-211-2/+3
| | | | | | | | Provide a macro to generate the mask for a domain, rather than using domain_val(, DOMAIN_MANAGER) which won't work when CPU_USE_DOMAINS is turned off. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
* ARM: domains: switch to keeping domain value in registerRussell King2015-08-211-5/+15
| | | | | | | | | | | | | Rather than modifying both the domain access control register and our per-thread copy, modify only the domain access control register, and use the per-thread copy to save and restore the register over context switches. We can also avoid the explicit initialisation of the init thread_info structure. This allows us to avoid needing to gain access to the thread information at the uaccess control sites. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
* ARM: fix set_domain() macroRussell King2012-07-051-9/+9
| | | | | | | | | Avoid polluting drivers with a set_domain() macro, which interferes with structure member names: drivers/net/wireless/ath/ath9k/dfs_pattern_detector.c:294:33: error: macro "set_domain" passed 2 arguments, but takes just 1 Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
* Disintegrate asm/system.h for ARMDavid Howells2012-03-281-0/+4
| | | | | | | | Disintegrate asm/system.h for ARM. Signed-off-by: David Howells <dhowells@redhat.com> cc: Russell King <linux@arm.linux.org.uk> cc: linux-arm-kernel@lists.infradead.org
* ARM: 7301/1: Rename the T() macro to TUSER() to avoid namespace conflictsCatalin Marinas2012-01-251-4/+4
| | | | | | | | | This macro is used to generate unprivileged accesses (LDRT/STRT) to user space. Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Acked-by: Nicolas Pitre <nico@linaro.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
* ARM: 6384/1: Remove the domain switching on ARMv6k/v7 CPUsCatalin Marinas2010-11-041-2/+29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* [ARM] move include/asm-arm to arch/arm/include/asmRussell King2008-08-021-0/+78
Move platform independent header files to arch/arm/include/asm, leaving those in asm/arch* and asm/plat* alone. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
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