- 05 9月, 2013 3 次提交
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由 Mischa Jonker 提交于
It prevents kernel parameters such as 'loglevel' from doing their job. Signed-off-by: NMischa Jonker <mjonker@synopsys.com> Signed-off-by: NVineet Gupta <vgupta@synopsys.com>
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由 Mischa Jonker 提交于
Some drivers require these, and ARC didn't had them yet. Signed-off-by: NMischa Jonker <mjonker@synopsys.com> Signed-off-by: NVineet Gupta <vgupta@synopsys.com>
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由 Noam Camus 提交于
Adding endian awarness to un-aligned access exception handling. Signed-off-by: NNoam Camus <noamc@ezchip.com> Signed-off-by: NVineet Gupta <vgupta@synopsys.com>
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- 31 8月, 2013 5 次提交
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由 Vineet Gupta 提交于
This helps remove asid-to-mm reverse map While mm->context.id contains the ASID assigned to a process, our ASID allocator also used asid_mm_map[] reverse map. In a new allocation cycle (mm->ASID >= @asid_cache), the Round Robin ASID allocator used this to check if new @asid_cache belonged to some mm2 (from prev cycle). If so, it could locate that mm using the ASID reverse map, and mark that mm as unallocated ASID, to force it to refresh at the time of switch_mm() However, for SMP, the reverse map has to be maintained per CPU, so becomes 2 dimensional, hence got rid of it. With reverse map gone, it is NOT possible to reach out to current assignee. So we track the ASID allocation generation/cycle and on every switch_mm(), check if the current generation of CPU ASID is same as mm's ASID; If not it is refreshed. (Based loosely on arch/sh implementation) Signed-off-by: NVineet Gupta <vgupta@synopsys.com>
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由 Vineet Gupta 提交于
ASID allocation changes/2 Use the fact that switch_mm() and activate_mm() are exactly same code now while acknowledging the semantical difference in comment Signed-off-by: NVineet Gupta <vgupta@synopsys.com>
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由 Vineet Gupta 提交于
ASID allocation changes/1 This patch does 2 things: (1) get_new_mmu_context() NOW moves mm->ASID to a new value ONLY if it was from a prev allocation cycle/generation OR if mm had no ASID allocated (vs. before would unconditionally moving to a new ASID) Callers desiring unconditional update of ASID, e.g.local_flush_tlb_mm() (for parent's address space invalidation at fork) need to first force the parent to an unallocated ASID. (2) get_new_mmu_context() always sets the MMU PID reg with unchanged/new ASID value. The gains are: - consolidation of all asid alloc logic into get_new_mmu_context() - avoiding code duplication in switch_mm() for PID reg setting - Enables future change to fold activate_mm() into switch_mm() Signed-off-by: NVineet Gupta <vgupta@synopsys.com>
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由 Vineet Gupta 提交于
-Asm code already has values of SW and HW ASID values, so they can be passed to the printing routine. Signed-off-by: NVineet Gupta <vgupta@synopsys.com>
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由 Vineet Gupta 提交于
Signed-off-by: NVineet Gupta <vgupta@synopsys.com>
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- 30 8月, 2013 3 次提交
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由 Vineet Gupta 提交于
Signed-off-by: NVineet Gupta <vgupta@synopsys.com>
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由 Vineet Gupta 提交于
This reorganizes the current TLB operations into psuedo-ops to better pair with MMUv4's native Insert/Delete operations Signed-off-by: NVineet Gupta <vgupta@synopsys.com>
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由 Vineet Gupta 提交于
With previous commit freeing up PTE bits, reassign them so as to: - Match the bit to H/w counterpart where possible (e.g. MMUv2 GLOBAL/PRESENT, this avoids a shift in create_tlb()) - Avoid holes in _PAGE_xxx definitions Signed-off-by: NVineet Gupta <vgupta@synopsys.com>
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- 29 8月, 2013 2 次提交
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由 Vineet Gupta 提交于
The current ARC VM code has 13 flags in Page Table entry: some software (accesed/dirty/non-linear-maps) and rest hardware specific. With 8k MMU page, we need 19 bits for addressing page frame so remaining 13 bits is just about enough to accomodate the current flags. In MMUv4 there are 2 additional flags, SZ (normal or super page) and WT (cache access mode write-thru) - and additionally PFN is 20 bits (vs. 19 before for 8k). Thus these can't be held in current PTE w/o making each entry 64bit wide. It seems there is some scope of compressing the current PTE flags (and freeing up a few bits). Currently PTE contains fully orthogonal distinct access permissions for kernel and user mode (Kr, Kw, Kx; Ur, Uw, Ux) which can be folded into one set (R, W, X). The translation of 3 PTE bits into 6 TLB bits (when programming the MMU) can be done based on following pre-requites/assumptions: 1. For kernel-mode-only translations (vmalloc: 0x7000_0000 to 0x7FFF_FFFF), PTE additionally has PAGE_GLOBAL flag set (and user space entries can never be global). Thus such a PTE can translate to Kr, Kw, Kx (as appropriate) and zero for User mode counterparts. 2. For non global entries, the PTE flags can be used to create mirrored K and U TLB bits. This is true after commit a950549c "ARC: copy_(to|from)_user() to honor usermode-access permissions" which ensured that user-space translations _MUST_ have same access permissions for both U/K mode accesses so that copy_{to,from}_user() play fair with fault based CoW break and such... There is no such thing as free lunch - the cost is slightly infalted TLB-Miss Handlers. Signed-off-by: NVineet Gupta <vgupta@synopsys.com>
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由 Vineet Gupta 提交于
* reduce editor lines taken by pt_regs * ARCompact ISA specific part of TLB Miss handlers clubbed together * cleanup some comments Signed-off-by: NVineet Gupta <vgupta@synopsys.com>
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- 26 8月, 2013 3 次提交
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由 Vineet Gupta 提交于
In the exception return path, for both U/K cases, intr are already disabled (for various existing reasons). So when we drop down to @restore_regs, we need not redo that. There was subtle issue - when intr were NOT being disabled for ret-to-kernel-but-no-preemption case - now fixed by moving the IRQ_DISABLE further up in @resume_kernel_mode. So what do we gain: * Shaves off a few insn in return path. * Eliminates the need for IRQ_DISABLE_SAVE assembler macro for ARCv2 hence allows for entry code sharing. Signed-off-by: NVineet Gupta <vgupta@synopsys.com>
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由 Vineet Gupta 提交于
After the recent cleanups, all the exception handlers now have same boilerplate prologue code. Move that into common macro. This reduces readability but helps greatly with sharing / duplicating entry code with ARCv2 ISA where the handlers are pretty much the same, just the entry prologue is different (due to hardware assist). Also while at it, add the missing FAKE_RET_FROM_EXCPN calls in couple of places to drop down to pure kernel mode (from exception mode) before jumping off into "C" code. Signed-off-by: NVineet Gupta <vgupta@synopsys.com>
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由 Vineet Gupta 提交于
Signed-off-by: NVineet Gupta <vgupta@synopsys.com>
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- 25 8月, 2013 1 次提交
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由 Joern Rennecke 提交于
For a search buffer, 2 byte aligned, strchr() was returning pointer outside of buffer (buf - 1) ------------->8---------------- // Input buffer (default 4 byte aigned) char *buffer = "1AA_"; // actual search start (to mimick 2 byte alignment) char *current_line = &(buffer[2]); // Character to search for char c = 'A'; char *c_pos = strchr(current_line, c); printf("%s\n", c_pos) --> 'AA_' as oppose to 'A_' ------------->8---------------- Reported-by: NAnton Kolesov <Anton.Kolesov@synopsys.com> Debugged-by: NAnton Kolesov <Anton.Kolesov@synopsys.com> Cc: <stable@vger.kernel.org> # [3.9 and 3.10] Cc: Noam Camus <noamc@ezchip.com> Signed-off-by: NJoern Rennecke <joern.rennecke@embecosm.com> Signed-off-by: NVineet Gupta <vgupta@synopsys.com> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 27 7月, 2013 1 次提交
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由 Vineet Gupta 提交于
Signed-off-by: NVineet Gupta <vgupta@synopsys.com>
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- 10 7月, 2013 1 次提交
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由 Johannes Weiner 提交于
A few remaining architectures directly kill the page faulting task in an out of memory situation. This is usually not a good idea since that task might not even use a significant amount of memory and so may not be the optimal victim to resolve the situation. Since 2.6.29's 1c0fe6e3 ("mm: invoke oom-killer from page fault") there is a hook that architecture page fault handlers are supposed to call to invoke the OOM killer and let it pick the right task to kill. Convert the remaining architectures over to this hook. To have the previous behavior of simply taking out the faulting task the vm.oom_kill_allocating_task sysctl can be set to 1. Signed-off-by: NJohannes Weiner <hannes@cmpxchg.org> Reviewed-by: NMichal Hocko <mhocko@suse.cz> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: NDavid Rientjes <rientjes@google.com> Acked-by: Vineet Gupta <vgupta@synopsys.com> [arch/arc bits] Cc: James Hogan <james.hogan@imgtec.com> Cc: David Howells <dhowells@redhat.com> Cc: Jonas Bonn <jonas@southpole.se> Cc: Chen Liqin <liqin.chen@sunplusct.com> Cc: Lennox Wu <lennox.wu@gmail.com> Cc: Chris Metcalf <cmetcalf@tilera.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 05 7月, 2013 1 次提交
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由 Dave Hansen 提交于
Original posting: http://lkml.kernel.org/r/20121214184202.F54094D9@kernel.stglabs.ibm.com Several architectures have similar stack debugging config options. They all pretty much do the same thing, some with slightly differing help text. This patch changes the architectures to instead enable a Kconfig boolean, and then use that boolean in the generic Kconfig.debug to present the actual menu option. This removes a bunch of duplication and adds consistency across arches. Signed-off-by: NDave Hansen <dave@linux.vnet.ibm.com> Reviewed-by: NH. Peter Anvin <hpa@zytor.com> Reviewed-by: NJames Hogan <james.hogan@imgtec.com> Acked-by: Chris Metcalf <cmetcalf@tilera.com> [for tile] Signed-off-by: NDave Hansen <dave.hansen@linux.intel.com> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 04 7月, 2013 4 次提交
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由 Jiang Liu 提交于
Prepare for removing num_physpages and simplify mem_init(). Signed-off-by: NJiang Liu <jiang.liu@huawei.com> Acked-by: Vineet Gupta <vgupta@synopsys.com> # for arch/arc Cc: James Hogan <james.hogan@imgtec.com> Cc: Rob Herring <rob.herring@calxeda.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Jiang Liu 提交于
Concentrate code to modify totalram_pages into the mm core, so the arch memory initialized code doesn't need to take care of it. With these changes applied, only following functions from mm core modify global variable totalram_pages: free_bootmem_late(), free_all_bootmem(), free_all_bootmem_node(), adjust_managed_page_count(). With this patch applied, it will be much more easier for us to keep totalram_pages and zone->managed_pages in consistence. Signed-off-by: NJiang Liu <jiang.liu@huawei.com> Acked-by: NDavid Howells <dhowells@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: <sworddragon2@aol.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Jianguo Wu <wujianguo@huawei.com> Cc: Joonsoo Kim <js1304@gmail.com> Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Marek Szyprowski <m.szyprowski@samsung.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Michel Lespinasse <walken@google.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Rik van Riel <riel@redhat.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Tang Chen <tangchen@cn.fujitsu.com> Cc: Tejun Heo <tj@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Wen Congyang <wency@cn.fujitsu.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> Cc: Yinghai Lu <yinghai@kernel.org> Cc: Russell King <rmk@arm.linux.org.uk> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Jiang Liu 提交于
Address more review comments from last round of code review. 1) Enhance free_reserved_area() to support poisoning freed memory with pattern '0'. This could be used to get rid of poison_init_mem() on ARM64. 2) A previous patch has disabled memory poison for initmem on s390 by mistake, so restore to the original behavior. 3) Remove redundant PAGE_ALIGN() when calling free_reserved_area(). Signed-off-by: NJiang Liu <jiang.liu@huawei.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: <sworddragon2@aol.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: David Howells <dhowells@redhat.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Jianguo Wu <wujianguo@huawei.com> Cc: Joonsoo Kim <js1304@gmail.com> Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Marek Szyprowski <m.szyprowski@samsung.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Michel Lespinasse <walken@google.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Rik van Riel <riel@redhat.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Tang Chen <tangchen@cn.fujitsu.com> Cc: Tejun Heo <tj@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Wen Congyang <wency@cn.fujitsu.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> Cc: Yinghai Lu <yinghai@kernel.org> Cc: Russell King <rmk@arm.linux.org.uk> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Jiang Liu 提交于
Change signature of free_reserved_area() according to Russell King's suggestion to fix following build warnings: arch/arm/mm/init.c: In function 'mem_init': arch/arm/mm/init.c:603:2: warning: passing argument 1 of 'free_reserved_area' makes integer from pointer without a cast [enabled by default] free_reserved_area(__va(PHYS_PFN_OFFSET), swapper_pg_dir, 0, NULL); ^ In file included from include/linux/mman.h:4:0, from arch/arm/mm/init.c:15: include/linux/mm.h:1301:22: note: expected 'long unsigned int' but argument is of type 'void *' extern unsigned long free_reserved_area(unsigned long start, unsigned long end, mm/page_alloc.c: In function 'free_reserved_area': >> mm/page_alloc.c:5134:3: warning: passing argument 1 of 'virt_to_phys' makes pointer from integer without a cast [enabled by default] In file included from arch/mips/include/asm/page.h:49:0, from include/linux/mmzone.h:20, from include/linux/gfp.h:4, from include/linux/mm.h:8, from mm/page_alloc.c:18: arch/mips/include/asm/io.h:119:29: note: expected 'const volatile void *' but argument is of type 'long unsigned int' mm/page_alloc.c: In function 'free_area_init_nodes': mm/page_alloc.c:5030:34: warning: array subscript is below array bounds [-Warray-bounds] Also address some minor code review comments. Signed-off-by: NJiang Liu <jiang.liu@huawei.com> Reported-by: NArnd Bergmann <arnd@arndb.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: <sworddragon2@aol.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: David Howells <dhowells@redhat.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Jianguo Wu <wujianguo@huawei.com> Cc: Joonsoo Kim <js1304@gmail.com> Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Marek Szyprowski <m.szyprowski@samsung.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Michel Lespinasse <walken@google.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Rik van Riel <riel@redhat.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Tang Chen <tangchen@cn.fujitsu.com> Cc: Tejun Heo <tj@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Wen Congyang <wency@cn.fujitsu.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> Cc: Yinghai Lu <yinghai@kernel.org> Cc: Russell King <rmk@arm.linux.org.uk> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 29 6月, 2013 2 次提交
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由 Al Viro 提交于
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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由 Al Viro 提交于
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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- 28 6月, 2013 2 次提交
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由 Christian Ruppert 提交于
Device tree and Kconfig updates for irqchip driver. Signed-off-by: NChristian Ruppert <christian.ruppert@abilis.com> Signed-off-by: NVineet Gupta <vgupta@synopsys.com>
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由 Alexey Brodkin 提交于
* Add arc_emac to DeviceTree DT description "Documentation/devicetree/bindings/net/arc_emac.txt". * Update defconfig correspondingly [vgupta: tweaked changelog] Signed-off-by: NAlexey Brodkin <abrodkin@synopsys.com> Signed-off-by: NVineet Gupta <vgupta@synopsys.com>
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- 27 6月, 2013 5 次提交
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由 Vineet Gupta 提交于
Signed-off-by: NVineet Gupta <vgupta@synopsys.com>
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由 Paul Gortmaker 提交于
The __cpuinit type of throwaway sections might have made sense some time ago when RAM was more constrained, but now the savings do not offset the cost and complications. For example, the fix in commit 5e427ec2 ("x86: Fix bit corruption at CPU resume time") is a good example of the nasty type of bugs that can be created with improper use of the various __init prefixes. After a discussion on LKML[1] it was decided that cpuinit should go the way of devinit and be phased out. Once all the users are gone, we can then finally remove the macros themselves from linux/init.h. Note that some harmless section mismatch warnings may result, since notify_cpu_starting() and cpu_up() are arch independent (kernel/cpu.c) are flagged as __cpuinit -- so if we remove the __cpuinit from arch specific callers, we will also get section mismatch warnings. As an intermediate step, we intend to turn the linux/init.h cpuinit content into no-ops as early as possible, since that will get rid of these warnings. In any case, they are temporary and harmless. This removes all the arch/arc uses of the __cpuinit macros from all C files. Currently arc does not have any __CPUINIT used in assembly files. [1] https://lkml.org/lkml/2013/5/20/589 Cc: Vineet Gupta <vgupta@synopsys.com> Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: NVineet Gupta <vgupta@synopsys.com>
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由 Vineet Gupta 提交于
LOAD_FAULT_PTE macro is expected to set r2 with faulting vaddr. However in case of CONFIG_ARC_DBG_TLB_MISS_COUNT, it was getting clobbered with statistics collection code. Fix latter by using a different register. Note that only I-TLB Miss handler was potentially affected. Signed-off-by: NVineet Gupta <vgupta@synopsys.com>
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由 Vineet Gupta 提交于
* No need to check for READ access in I-TLB Miss handler * Redundant PAGE_PRESENT update in PTE Post TLB entry installation, in updating PTE for software accessed/dity bits, no need to update PAGE_PRESENT since it will already be set. Infact the entry won't have installed if !PAGE_PRESENT. Signed-off-by: NVineet Gupta <vgupta@synopsys.com>
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由 Vineet Gupta 提交于
* DWARF unwinder related + Force DWARF2 compliant .debug_frame (gcc 4.8 defaults to DWARF4 which kernel unwinder can't grok). + Discard the additional .eh_frame generated + Discard the dwarf4 debug info generated by -gdwarf-2 for normal no debug case * 4.8 already uses arc600 multilibs for -mno-mpy * switch to using uclibc compiler (to get -mmedium-calls and -mno-sdata) and also since buildroot can only use 1 toolchain Signed-off-by: NVineet Gupta <vgupta@synopsys.com>
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- 26 6月, 2013 4 次提交
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由 Christian Ruppert 提交于
This patch makes the SDA hold time configurable through device tree. Signed-off-by: NChristian Ruppert <christian.ruppert@abilis.com> Signed-off-by: NPierrick Hascoet <pierrick.hascoet@abilis.com> Acked-by: Vineet Gupta <vgupta@synopsys.com> for arch/arc bits Signed-off-by: NWolfram Sang <wsa@the-dreams.de>
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由 Vineet Gupta 提交于
Otherwise early boot exceptions such as instructions errors due to configuration mismatch between kernel and hardware go off to la-la land, as opposed to hitting the handler and panic()'ing properly. Signed-off-by: NVineet Gupta <vgupta@synopsys.com>
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由 Vineet Gupta 提交于
With ECR now part of pt_regs * No need to propagate from lowest asm handlers as arg * No need to save it in tsk->thread.cause_code * Avoid bit chopping to access the bit-fields More code consolidation, cleanup Signed-off-by: NVineet Gupta <vgupta@synopsys.com>
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由 Vineet Gupta 提交于
pt_regs->event was set with artificial values to identify the low level system event (syscall trap / breakpoint trap / exceptions / interrupts) With r8 saving out of the way, the full word can be used to save real ECR (Exception Cause Register) which helps idenify the event naturally, including additional info such as cause code, param. Only for Interrupts, where ECR is not applicable, do we resort to synthetic non ECR values. SAVE_ALL_TRAP/EXCEPTIONS can now be merged as they both use ECR with different runtime values. The ptrace helpers now use the sub-fields of ECR to distinguish the events (e.g. vector 0x25 is trap, param 0 is syscall...) The following benefits will follow: (1) This centralizes the location of where ECR is saved and will allow the cleanup of task->thread.cause_code ECR placeholder which is set in non-uniform way. Then ARC VM code can safely rely on it being there for purpose of finer grained VM_EXEC dcache flush (based on exec fault: I-TLB Miss) (2) Further, ECR being passed around from low level handlers as arg can be eliminated as it is part of standard reg-file in pt_regs Signed-off-by: NVineet Gupta <vgupta@synopsys.com>
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- 22 6月, 2013 3 次提交
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由 Vineet Gupta 提交于
Historically, pt_regs have had orig_r8, an overloaded container for (1) backup copy of r8 (syscall number Trap Exceptions) (2) additional system state: (syscall/Exception/Interrupt) There is no point in keeping (1) since syscall number is never clobbered in-place, in pt_regs, unlike r0 which duals as first syscall arg as well as syscall return value and in case of syscall restart, the orig arg0 needs restoring (from orig_r0) after having been updated in-place with syscall ret value. This further paves way to convert (2) to contain ECR itself (rather than current madeup values) Signed-off-by: NVineet Gupta <vgupta@synopsys.com>
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由 Vineet Gupta 提交于
(This is a VERY IMP change for low level interrupt/exception handling) ----------------------------------------------------------------------- WHAT ----------------------------------------------------------------------- * User 25 now saved in pt_regs->user_r25 (vs. tsk->thread_info.user_r25) * This allows Low level interrupt code to unconditionally save r25 (vs. the prev version which would only do it for U->K transition). Ofcourse for nested interrupts, only the pt_regs->user_r25 of bottom-most frame is useful. * simplifies the interrupt prologue/epilogue * Needed for ARCv2 ISA code and done here to keep design similar with ARCompact event handling ----------------------------------------------------------------------- WHY ------------------------------------------------------------------------- With CONFIG_ARC_CURR_IN_REG, r25 is used to cache "current" task pointer in kernel mode. So when entering kernel mode from User Mode - user r25 is specially safe-kept (it being a callee reg is NOT part of pt_regs which are saved by default on each interrupt/trap/exception) - r25 loaded with current task pointer. Further, if interrupt was taken in kernel mode, this is skipped since we know that r25 already has valid "current" pointer. With 2 level of interrupts in ARCompact ISA, detecting this is difficult but still possible, since we could be in kernel mode but r25 not already saved (in fact the stack itself might not have been switched). A. User mode B. L1 IRQ taken C. L2 IRQ taken (while on 1st line of L1 ISR) So in #C, although in kernel mode, r25 not saved (infact SP not switched at all) Given that ARcompact has manual stack switching, we could use a bit of trickey - The low level code would make sure that SP is only set to kernel mode value at the very end (after saving r25). So a non kernel mode SP, even if in kernel mode, meant r25 was NOT saved. The same paradigm won't work in ARCv2 ISA since SP is auto-switched so it's setting can't be delayed/constrained. Signed-off-by: NVineet Gupta <vgupta@synopsys.com>
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由 Vineet Gupta 提交于
This paves way for further simplifications. There's an overhead of 1 insn for the non-common case of interrupt taken from kernel mode. Signed-off-by: NVineet Gupta <vgupta@synopsys.com>
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