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OpenCloudOS-Kernel/arch/arm/include/asm/barrier.h

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Disintegrate asm/system.h for ARM 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
2012-03-29 01:30:01 +08:00
#ifndef __ASM_BARRIER_H
#define __ASM_BARRIER_H
#ifndef __ASSEMBLY__
#define nop() __asm__ __volatile__("mov\tr0,r0\t@ nop\n\t");
#if __LINUX_ARM_ARCH__ >= 7 || \
(__LINUX_ARM_ARCH__ == 6 && defined(CONFIG_CPU_32v6K))
#define sev() __asm__ __volatile__ ("sev" : : : "memory")
#define wfe() __asm__ __volatile__ ("wfe" : : : "memory")
#define wfi() __asm__ __volatile__ ("wfi" : : : "memory")
#endif
#if __LINUX_ARM_ARCH__ >= 7
ARM: barrier: allow options to be passed to memory barrier instructions On ARMv7, the memory barrier instructions take an optional `option' field which can be used to constrain the effects of a memory barrier based on shareability and access type. This patch allows the caller to pass these options if required, and updates the smp_*() barriers to request inner-shareable barriers, affecting only stores for the _wmb variant. wmb() is also changed to use the -st version of dsb. Reported-by: Albin Tonnerre <albin.tonnerre@arm.com> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com>
2013-05-11 01:07:19 +08:00
#define isb(option) __asm__ __volatile__ ("isb " #option : : : "memory")
#define dsb(option) __asm__ __volatile__ ("dsb " #option : : : "memory")
#define dmb(option) __asm__ __volatile__ ("dmb " #option : : : "memory")
Disintegrate asm/system.h for ARM 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
2012-03-29 01:30:01 +08:00
#elif defined(CONFIG_CPU_XSC3) || __LINUX_ARM_ARCH__ == 6
ARM: barrier: allow options to be passed to memory barrier instructions On ARMv7, the memory barrier instructions take an optional `option' field which can be used to constrain the effects of a memory barrier based on shareability and access type. This patch allows the caller to pass these options if required, and updates the smp_*() barriers to request inner-shareable barriers, affecting only stores for the _wmb variant. wmb() is also changed to use the -st version of dsb. Reported-by: Albin Tonnerre <albin.tonnerre@arm.com> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com>
2013-05-11 01:07:19 +08:00
#define isb(x) __asm__ __volatile__ ("mcr p15, 0, %0, c7, c5, 4" \
Disintegrate asm/system.h for ARM 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
2012-03-29 01:30:01 +08:00
: : "r" (0) : "memory")
ARM: barrier: allow options to be passed to memory barrier instructions On ARMv7, the memory barrier instructions take an optional `option' field which can be used to constrain the effects of a memory barrier based on shareability and access type. This patch allows the caller to pass these options if required, and updates the smp_*() barriers to request inner-shareable barriers, affecting only stores for the _wmb variant. wmb() is also changed to use the -st version of dsb. Reported-by: Albin Tonnerre <albin.tonnerre@arm.com> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com>
2013-05-11 01:07:19 +08:00
#define dsb(x) __asm__ __volatile__ ("mcr p15, 0, %0, c7, c10, 4" \
Disintegrate asm/system.h for ARM 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
2012-03-29 01:30:01 +08:00
: : "r" (0) : "memory")
ARM: barrier: allow options to be passed to memory barrier instructions On ARMv7, the memory barrier instructions take an optional `option' field which can be used to constrain the effects of a memory barrier based on shareability and access type. This patch allows the caller to pass these options if required, and updates the smp_*() barriers to request inner-shareable barriers, affecting only stores for the _wmb variant. wmb() is also changed to use the -st version of dsb. Reported-by: Albin Tonnerre <albin.tonnerre@arm.com> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com>
2013-05-11 01:07:19 +08:00
#define dmb(x) __asm__ __volatile__ ("mcr p15, 0, %0, c7, c10, 5" \
Disintegrate asm/system.h for ARM 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
2012-03-29 01:30:01 +08:00
: : "r" (0) : "memory")
#elif defined(CONFIG_CPU_FA526)
ARM: barrier: allow options to be passed to memory barrier instructions On ARMv7, the memory barrier instructions take an optional `option' field which can be used to constrain the effects of a memory barrier based on shareability and access type. This patch allows the caller to pass these options if required, and updates the smp_*() barriers to request inner-shareable barriers, affecting only stores for the _wmb variant. wmb() is also changed to use the -st version of dsb. Reported-by: Albin Tonnerre <albin.tonnerre@arm.com> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com>
2013-05-11 01:07:19 +08:00
#define isb(x) __asm__ __volatile__ ("mcr p15, 0, %0, c7, c5, 4" \
Disintegrate asm/system.h for ARM 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
2012-03-29 01:30:01 +08:00
: : "r" (0) : "memory")
ARM: barrier: allow options to be passed to memory barrier instructions On ARMv7, the memory barrier instructions take an optional `option' field which can be used to constrain the effects of a memory barrier based on shareability and access type. This patch allows the caller to pass these options if required, and updates the smp_*() barriers to request inner-shareable barriers, affecting only stores for the _wmb variant. wmb() is also changed to use the -st version of dsb. Reported-by: Albin Tonnerre <albin.tonnerre@arm.com> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com>
2013-05-11 01:07:19 +08:00
#define dsb(x) __asm__ __volatile__ ("mcr p15, 0, %0, c7, c10, 4" \
Disintegrate asm/system.h for ARM 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
2012-03-29 01:30:01 +08:00
: : "r" (0) : "memory")
ARM: barrier: allow options to be passed to memory barrier instructions On ARMv7, the memory barrier instructions take an optional `option' field which can be used to constrain the effects of a memory barrier based on shareability and access type. This patch allows the caller to pass these options if required, and updates the smp_*() barriers to request inner-shareable barriers, affecting only stores for the _wmb variant. wmb() is also changed to use the -st version of dsb. Reported-by: Albin Tonnerre <albin.tonnerre@arm.com> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com>
2013-05-11 01:07:19 +08:00
#define dmb(x) __asm__ __volatile__ ("" : : : "memory")
Disintegrate asm/system.h for ARM 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
2012-03-29 01:30:01 +08:00
#else
ARM: barrier: allow options to be passed to memory barrier instructions On ARMv7, the memory barrier instructions take an optional `option' field which can be used to constrain the effects of a memory barrier based on shareability and access type. This patch allows the caller to pass these options if required, and updates the smp_*() barriers to request inner-shareable barriers, affecting only stores for the _wmb variant. wmb() is also changed to use the -st version of dsb. Reported-by: Albin Tonnerre <albin.tonnerre@arm.com> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com>
2013-05-11 01:07:19 +08:00
#define isb(x) __asm__ __volatile__ ("" : : : "memory")
#define dsb(x) __asm__ __volatile__ ("mcr p15, 0, %0, c7, c10, 4" \
Disintegrate asm/system.h for ARM 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
2012-03-29 01:30:01 +08:00
: : "r" (0) : "memory")
ARM: barrier: allow options to be passed to memory barrier instructions On ARMv7, the memory barrier instructions take an optional `option' field which can be used to constrain the effects of a memory barrier based on shareability and access type. This patch allows the caller to pass these options if required, and updates the smp_*() barriers to request inner-shareable barriers, affecting only stores for the _wmb variant. wmb() is also changed to use the -st version of dsb. Reported-by: Albin Tonnerre <albin.tonnerre@arm.com> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com>
2013-05-11 01:07:19 +08:00
#define dmb(x) __asm__ __volatile__ ("" : : : "memory")
Disintegrate asm/system.h for ARM 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
2012-03-29 01:30:01 +08:00
#endif
ARM: move heavy barrier support out of line The existing memory barrier macro causes a significant amount of code to be inserted inline at every call site. For example, in gpio_set_irq_type(), we have this for mb(): c0344c08: f57ff04e dsb st c0344c0c: e59f8190 ldr r8, [pc, #400] ; c0344da4 <gpio_set_irq_type+0x230> c0344c10: e3590004 cmp r9, #4 c0344c14: e5983014 ldr r3, [r8, #20] c0344c18: 0a000054 beq c0344d70 <gpio_set_irq_type+0x1fc> c0344c1c: e3530000 cmp r3, #0 c0344c20: 0a000004 beq c0344c38 <gpio_set_irq_type+0xc4> c0344c24: e50b2030 str r2, [fp, #-48] ; 0xffffffd0 c0344c28: e50bc034 str ip, [fp, #-52] ; 0xffffffcc c0344c2c: e12fff33 blx r3 c0344c30: e51bc034 ldr ip, [fp, #-52] ; 0xffffffcc c0344c34: e51b2030 ldr r2, [fp, #-48] ; 0xffffffd0 c0344c38: e5963004 ldr r3, [r6, #4] Moving the outer_cache_sync() call out of line reduces the impact of the barrier: c0344968: f57ff04e dsb st c034496c: e35a0004 cmp sl, #4 c0344970: e50b2030 str r2, [fp, #-48] ; 0xffffffd0 c0344974: 0a000044 beq c0344a8c <gpio_set_irq_type+0x1b8> c0344978: ebf363dd bl c001d8f4 <arm_heavy_mb> c034497c: e5953004 ldr r3, [r5, #4] This should reduce the cache footprint of this code. Overall, this results in a reduction of around 20K in the kernel size: text data bss dec hex filename 10773970 667392 10369656 21811018 14ccf4a ../build/imx6/vmlinux-old 10754219 667392 10369656 21791267 14c8223 ../build/imx6/vmlinux-new Another advantage to this approach is that we can finally resolve the issue of SoCs which have their own memory barrier requirements within multiplatform kernels (such as OMAP.) Here, the bus interconnects need additional handling to ensure that writes become visible in the correct order (eg, between dma_map() operations, writes to DMA coherent memory, and MMIO accesses.) Acked-by: Tony Lindgren <tony@atomide.com> Acked-by: Richard Woodruff <r-woodruff2@ti.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2015-06-02 06:44:46 +08:00
#ifdef CONFIG_ARM_HEAVY_MB
ARM: add soc memory barrier extension Add an extension to the heavy barrier code to allow a SoC specific memory barrier function to be provided. This is needed for platforms where the interconnect has weak ordering, and thus needs assistance to ensure that memory writes are properly visible in the correct order to other parts of the system. Acked-by: Tony Lindgren <tony@atomide.com> Acked-by: Richard Woodruff <r-woodruff2@ti.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2015-06-03 20:10:16 +08:00
extern void (*soc_mb)(void);
ARM: move heavy barrier support out of line The existing memory barrier macro causes a significant amount of code to be inserted inline at every call site. For example, in gpio_set_irq_type(), we have this for mb(): c0344c08: f57ff04e dsb st c0344c0c: e59f8190 ldr r8, [pc, #400] ; c0344da4 <gpio_set_irq_type+0x230> c0344c10: e3590004 cmp r9, #4 c0344c14: e5983014 ldr r3, [r8, #20] c0344c18: 0a000054 beq c0344d70 <gpio_set_irq_type+0x1fc> c0344c1c: e3530000 cmp r3, #0 c0344c20: 0a000004 beq c0344c38 <gpio_set_irq_type+0xc4> c0344c24: e50b2030 str r2, [fp, #-48] ; 0xffffffd0 c0344c28: e50bc034 str ip, [fp, #-52] ; 0xffffffcc c0344c2c: e12fff33 blx r3 c0344c30: e51bc034 ldr ip, [fp, #-52] ; 0xffffffcc c0344c34: e51b2030 ldr r2, [fp, #-48] ; 0xffffffd0 c0344c38: e5963004 ldr r3, [r6, #4] Moving the outer_cache_sync() call out of line reduces the impact of the barrier: c0344968: f57ff04e dsb st c034496c: e35a0004 cmp sl, #4 c0344970: e50b2030 str r2, [fp, #-48] ; 0xffffffd0 c0344974: 0a000044 beq c0344a8c <gpio_set_irq_type+0x1b8> c0344978: ebf363dd bl c001d8f4 <arm_heavy_mb> c034497c: e5953004 ldr r3, [r5, #4] This should reduce the cache footprint of this code. Overall, this results in a reduction of around 20K in the kernel size: text data bss dec hex filename 10773970 667392 10369656 21811018 14ccf4a ../build/imx6/vmlinux-old 10754219 667392 10369656 21791267 14c8223 ../build/imx6/vmlinux-new Another advantage to this approach is that we can finally resolve the issue of SoCs which have their own memory barrier requirements within multiplatform kernels (such as OMAP.) Here, the bus interconnects need additional handling to ensure that writes become visible in the correct order (eg, between dma_map() operations, writes to DMA coherent memory, and MMIO accesses.) Acked-by: Tony Lindgren <tony@atomide.com> Acked-by: Richard Woodruff <r-woodruff2@ti.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2015-06-02 06:44:46 +08:00
extern void arm_heavy_mb(void);
#define __arm_heavy_mb(x...) do { dsb(x); arm_heavy_mb(); } while (0)
#else
#define __arm_heavy_mb(x...) dsb(x)
#endif
Disintegrate asm/system.h for ARM 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
2012-03-29 01:30:01 +08:00
#ifdef CONFIG_ARCH_HAS_BARRIERS
#include <mach/barriers.h>
#elif defined(CONFIG_ARM_DMA_MEM_BUFFERABLE) || defined(CONFIG_SMP)
ARM: move heavy barrier support out of line The existing memory barrier macro causes a significant amount of code to be inserted inline at every call site. For example, in gpio_set_irq_type(), we have this for mb(): c0344c08: f57ff04e dsb st c0344c0c: e59f8190 ldr r8, [pc, #400] ; c0344da4 <gpio_set_irq_type+0x230> c0344c10: e3590004 cmp r9, #4 c0344c14: e5983014 ldr r3, [r8, #20] c0344c18: 0a000054 beq c0344d70 <gpio_set_irq_type+0x1fc> c0344c1c: e3530000 cmp r3, #0 c0344c20: 0a000004 beq c0344c38 <gpio_set_irq_type+0xc4> c0344c24: e50b2030 str r2, [fp, #-48] ; 0xffffffd0 c0344c28: e50bc034 str ip, [fp, #-52] ; 0xffffffcc c0344c2c: e12fff33 blx r3 c0344c30: e51bc034 ldr ip, [fp, #-52] ; 0xffffffcc c0344c34: e51b2030 ldr r2, [fp, #-48] ; 0xffffffd0 c0344c38: e5963004 ldr r3, [r6, #4] Moving the outer_cache_sync() call out of line reduces the impact of the barrier: c0344968: f57ff04e dsb st c034496c: e35a0004 cmp sl, #4 c0344970: e50b2030 str r2, [fp, #-48] ; 0xffffffd0 c0344974: 0a000044 beq c0344a8c <gpio_set_irq_type+0x1b8> c0344978: ebf363dd bl c001d8f4 <arm_heavy_mb> c034497c: e5953004 ldr r3, [r5, #4] This should reduce the cache footprint of this code. Overall, this results in a reduction of around 20K in the kernel size: text data bss dec hex filename 10773970 667392 10369656 21811018 14ccf4a ../build/imx6/vmlinux-old 10754219 667392 10369656 21791267 14c8223 ../build/imx6/vmlinux-new Another advantage to this approach is that we can finally resolve the issue of SoCs which have their own memory barrier requirements within multiplatform kernels (such as OMAP.) Here, the bus interconnects need additional handling to ensure that writes become visible in the correct order (eg, between dma_map() operations, writes to DMA coherent memory, and MMIO accesses.) Acked-by: Tony Lindgren <tony@atomide.com> Acked-by: Richard Woodruff <r-woodruff2@ti.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2015-06-02 06:44:46 +08:00
#define mb() __arm_heavy_mb()
Disintegrate asm/system.h for ARM 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
2012-03-29 01:30:01 +08:00
#define rmb() dsb()
ARM: move heavy barrier support out of line The existing memory barrier macro causes a significant amount of code to be inserted inline at every call site. For example, in gpio_set_irq_type(), we have this for mb(): c0344c08: f57ff04e dsb st c0344c0c: e59f8190 ldr r8, [pc, #400] ; c0344da4 <gpio_set_irq_type+0x230> c0344c10: e3590004 cmp r9, #4 c0344c14: e5983014 ldr r3, [r8, #20] c0344c18: 0a000054 beq c0344d70 <gpio_set_irq_type+0x1fc> c0344c1c: e3530000 cmp r3, #0 c0344c20: 0a000004 beq c0344c38 <gpio_set_irq_type+0xc4> c0344c24: e50b2030 str r2, [fp, #-48] ; 0xffffffd0 c0344c28: e50bc034 str ip, [fp, #-52] ; 0xffffffcc c0344c2c: e12fff33 blx r3 c0344c30: e51bc034 ldr ip, [fp, #-52] ; 0xffffffcc c0344c34: e51b2030 ldr r2, [fp, #-48] ; 0xffffffd0 c0344c38: e5963004 ldr r3, [r6, #4] Moving the outer_cache_sync() call out of line reduces the impact of the barrier: c0344968: f57ff04e dsb st c034496c: e35a0004 cmp sl, #4 c0344970: e50b2030 str r2, [fp, #-48] ; 0xffffffd0 c0344974: 0a000044 beq c0344a8c <gpio_set_irq_type+0x1b8> c0344978: ebf363dd bl c001d8f4 <arm_heavy_mb> c034497c: e5953004 ldr r3, [r5, #4] This should reduce the cache footprint of this code. Overall, this results in a reduction of around 20K in the kernel size: text data bss dec hex filename 10773970 667392 10369656 21811018 14ccf4a ../build/imx6/vmlinux-old 10754219 667392 10369656 21791267 14c8223 ../build/imx6/vmlinux-new Another advantage to this approach is that we can finally resolve the issue of SoCs which have their own memory barrier requirements within multiplatform kernels (such as OMAP.) Here, the bus interconnects need additional handling to ensure that writes become visible in the correct order (eg, between dma_map() operations, writes to DMA coherent memory, and MMIO accesses.) Acked-by: Tony Lindgren <tony@atomide.com> Acked-by: Richard Woodruff <r-woodruff2@ti.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2015-06-02 06:44:46 +08:00
#define wmb() __arm_heavy_mb(st)
arch: Add lightweight memory barriers dma_rmb() and dma_wmb() There are a number of situations where the mandatory barriers rmb() and wmb() are used to order memory/memory operations in the device drivers and those barriers are much heavier than they actually need to be. For example in the case of PowerPC wmb() calls the heavy-weight sync instruction when for coherent memory operations all that is really needed is an lsync or eieio instruction. This commit adds a coherent only version of the mandatory memory barriers rmb() and wmb(). In most cases this should result in the barrier being the same as the SMP barriers for the SMP case, however in some cases we use a barrier that is somewhere in between rmb() and smp_rmb(). For example on ARM the rmb barriers break down as follows: Barrier Call Explanation --------- -------- ---------------------------------- rmb() dsb() Data synchronization barrier - system dma_rmb() dmb(osh) data memory barrier - outer sharable smp_rmb() dmb(ish) data memory barrier - inner sharable These new barriers are not as safe as the standard rmb() and wmb(). Specifically they do not guarantee ordering between coherent and incoherent memories. The primary use case for these would be to enforce ordering of reads and writes when accessing coherent memory that is shared between the CPU and a device. It may also be noted that there is no dma_mb(). Most architectures don't provide a good mechanism for performing a coherent only full barrier without resorting to the same mechanism used in mb(). As such there isn't much to be gained in trying to define such a function. Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Cc: Michael Ellerman <michael@ellerman.id.au> Cc: Michael Neuling <mikey@neuling.org> Cc: Russell King <linux@arm.linux.org.uk> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: David Miller <davem@davemloft.net> Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Acked-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Alexander Duyck <alexander.h.duyck@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-12-12 07:02:06 +08:00
#define dma_rmb() dmb(osh)
#define dma_wmb() dmb(oshst)
Disintegrate asm/system.h for ARM 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
2012-03-29 01:30:01 +08:00
#else
ARM: kill off arch_is_coherent With ixp2xxx removed, there are no platforms that define arch_is_coherent, so the last occurrences of arch_is_coherent can be removed. Any new platform with coherent i/o should use coherent dma mapping functions. Signed-off-by: Rob Herring <rob.herring@calxeda.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Marek Szyprowski <m.szyprowski@samsung.com> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
2012-08-21 18:26:24 +08:00
#define mb() barrier()
#define rmb() barrier()
#define wmb() barrier()
arch: Add lightweight memory barriers dma_rmb() and dma_wmb() There are a number of situations where the mandatory barriers rmb() and wmb() are used to order memory/memory operations in the device drivers and those barriers are much heavier than they actually need to be. For example in the case of PowerPC wmb() calls the heavy-weight sync instruction when for coherent memory operations all that is really needed is an lsync or eieio instruction. This commit adds a coherent only version of the mandatory memory barriers rmb() and wmb(). In most cases this should result in the barrier being the same as the SMP barriers for the SMP case, however in some cases we use a barrier that is somewhere in between rmb() and smp_rmb(). For example on ARM the rmb barriers break down as follows: Barrier Call Explanation --------- -------- ---------------------------------- rmb() dsb() Data synchronization barrier - system dma_rmb() dmb(osh) data memory barrier - outer sharable smp_rmb() dmb(ish) data memory barrier - inner sharable These new barriers are not as safe as the standard rmb() and wmb(). Specifically they do not guarantee ordering between coherent and incoherent memories. The primary use case for these would be to enforce ordering of reads and writes when accessing coherent memory that is shared between the CPU and a device. It may also be noted that there is no dma_mb(). Most architectures don't provide a good mechanism for performing a coherent only full barrier without resorting to the same mechanism used in mb(). As such there isn't much to be gained in trying to define such a function. Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Cc: Michael Ellerman <michael@ellerman.id.au> Cc: Michael Neuling <mikey@neuling.org> Cc: Russell King <linux@arm.linux.org.uk> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: David Miller <davem@davemloft.net> Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Acked-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Alexander Duyck <alexander.h.duyck@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-12-12 07:02:06 +08:00
#define dma_rmb() barrier()
#define dma_wmb() barrier()
Disintegrate asm/system.h for ARM 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
2012-03-29 01:30:01 +08:00
#endif
arm: define __smp_xxx This defines __smp_xxx barriers for arm, for use by virtualization. smp_xxx barriers are removed as they are defined correctly by asm-generic/barriers.h This reduces the amount of arch-specific boiler-plate code. Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Russell King <rmk+kernel@arm.linux.org.uk> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
2015-12-27 21:04:42 +08:00
#define __smp_mb() dmb(ish)
#define __smp_rmb() __smp_mb()
#define __smp_wmb() dmb(ishst)
Disintegrate asm/system.h for ARM 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
2012-03-29 01:30:01 +08:00
arm: reuse asm-generic/barrier.h On arm smp_store_mb, read_barrier_depends, smp_read_barrier_depends, smp_store_release, smp_load_acquire, smp_mb__before_atomic and smp_mb__after_atomic match the asm-generic variants exactly. Drop the local definitions and pull in asm-generic/barrier.h instead. This is in preparation to refactoring this code area. Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Russell King <rmk+kernel@arm.linux.org.uk> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
2015-12-21 15:22:18 +08:00
#include <asm-generic/barrier.h>
arch,arm: Convert smp_mb__*() ARM uses ll/sc primitives that do not imply barriers for all regular atomic ops, therefore smp_mb__{before,after} need be a full barrier. Since ARM doesn't use asm-generic/barrier.h include the required definitions in its asm/barrier.h Signed-off-by: Peter Zijlstra <peterz@infradead.org> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Link: http://lkml.kernel.org/n/tip-yijo7sglsl7uusbp13upcuvo@git.kernel.org Cc: Albin Tonnerre <albin.tonnerre@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Chen Gang <gang.chen@asianux.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Nicolas Pitre <nico@linaro.org> Cc: Russell King <linux@arm.linux.org.uk> Cc: Victor Kamensky <victor.kamensky@linaro.org> Cc: Will Deacon <will.deacon@arm.com> Cc: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-03-13 00:11:00 +08:00
Disintegrate asm/system.h for ARM 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
2012-03-29 01:30:01 +08:00
#endif /* !__ASSEMBLY__ */
#endif /* __ASM_BARRIER_H */