diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2013-07-02 13:43:38 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2013-07-02 13:43:38 -0700 |
commit | 3883cbb6c1bda013a3ce2dbdab7dc97c52e4a232 (patch) | |
tree | 5b69f83b049d24ac81123ac954ca8c9128e48443 /arch/arm/kernel/entry-header.S | |
parent | d2033f2c1d1de2239ded15e478ddb4028f192a15 (diff) | |
parent | 1eb92b24e243085d242cf5ffd64829bba70972e1 (diff) |
Merge tag 'soc-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc
Pull ARM SoC specific changes from Arnd Bergmann:
"These changes are all to SoC-specific code, a total of 33 branches on
17 platforms were pulled into this. Like last time, Renesas sh-mobile
is now the platform with the most changes, followed by OMAP and
EXYNOS.
Two new platforms, TI Keystone and Rockchips RK3xxx are added in this
branch, both containing almost no platform specific code at all, since
they are using generic subsystem interfaces for clocks, pinctrl,
interrupts etc. The device drivers are getting merged through the
respective subsystem maintainer trees.
One more SoC (u300) is now multiplatform capable and several others
(shmobile, exynos, msm, integrator, kirkwood, clps711x) are moving
towards that goal with this series but need more work.
Also noteworthy is the work on PCI here, which is traditionally part
of the SoC specific code. With the changes done by Thomas Petazzoni,
we can now more easily have PCI host controller drivers as loadable
modules and keep them separate from the platform code in
drivers/pci/host. This has already led to the discovery that three
platforms (exynos, spear and imx) are actually using an identical PCIe
host controller and will be able to share a driver once support for
spear and imx is added."
* tag 'soc-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc: (480 commits)
ARM: integrator: let pciv3 use mem/premem from device tree
ARM: integrator: set local side PCI addresses right
ARM: dts: Add pcie controller node for exynos5440-ssdk5440
ARM: dts: Add pcie controller node for Samsung EXYNOS5440 SoC
ARM: EXYNOS: Enable PCIe support for Exynos5440
pci: Add PCIe driver for Samsung Exynos
ARM: OMAP5: voltagedomain data: remove temporary OMAP4 voltage data
ARM: keystone: Move CPU bringup code to dedicated asm file
ARM: multiplatform: always pick one CPU type
ARM: imx: select syscon for IMX6SL
ARM: keystone: select ARM_ERRATA_798181 only for SMP
ARM: imx: Synertronixx scb9328 needs to select SOC_IMX1
ARM: OMAP2+: AM43x: resolve SMP related build error
dmaengine: edma: enable build for AM33XX
ARM: edma: Add EDMA crossbar event mux support
ARM: edma: Add DT and runtime PM support to the private EDMA API
dmaengine: edma: Add TI EDMA device tree binding
arm: add basic support for Rockchip RK3066a boards
arm: add debug uarts for rockchip rk29xx and rk3xxx series
arm: Add basic clocks for Rockchip rk3066a SoCs
...
Diffstat (limited to 'arch/arm/kernel/entry-header.S')
-rw-r--r-- | arch/arm/kernel/entry-header.S | 124 |
1 files changed, 124 insertions, 0 deletions
diff --git a/arch/arm/kernel/entry-header.S b/arch/arm/kernel/entry-header.S index 160f3376ba6..de23a9beed1 100644 --- a/arch/arm/kernel/entry-header.S +++ b/arch/arm/kernel/entry-header.S @@ -5,6 +5,7 @@ #include <asm/asm-offsets.h> #include <asm/errno.h> #include <asm/thread_info.h> +#include <asm/v7m.h> @ Bad Abort numbers @ ----------------- @@ -44,6 +45,116 @@ #endif .endm +#ifdef CONFIG_CPU_V7M +/* + * ARMv7-M exception entry/exit macros. + * + * xPSR, ReturnAddress(), LR (R14), R12, R3, R2, R1, and R0 are + * automatically saved on the current stack (32 words) before + * switching to the exception stack (SP_main). + * + * If exception is taken while in user mode, SP_main is + * empty. Otherwise, SP_main is aligned to 64 bit automatically + * (CCR.STKALIGN set). + * + * Linux assumes that the interrupts are disabled when entering an + * exception handler and it may BUG if this is not the case. Interrupts + * are disabled during entry and reenabled in the exit macro. + * + * v7m_exception_slow_exit is used when returning from SVC or PendSV. + * When returning to kernel mode, we don't return from exception. + */ + .macro v7m_exception_entry + @ determine the location of the registers saved by the core during + @ exception entry. Depending on the mode the cpu was in when the + @ exception happend that is either on the main or the process stack. + @ Bit 2 of EXC_RETURN stored in the lr register specifies which stack + @ was used. + tst lr, #EXC_RET_STACK_MASK + mrsne r12, psp + moveq r12, sp + + @ we cannot rely on r0-r3 and r12 matching the value saved in the + @ exception frame because of tail-chaining. So these have to be + @ reloaded. + ldmia r12!, {r0-r3} + + @ Linux expects to have irqs off. Do it here before taking stack space + cpsid i + + sub sp, #S_FRAME_SIZE-S_IP + stmdb sp!, {r0-r11} + + @ load saved r12, lr, return address and xPSR. + @ r0-r7 are used for signals and never touched from now on. Clobbering + @ r8-r12 is OK. + mov r9, r12 + ldmia r9!, {r8, r10-r12} + + @ calculate the original stack pointer value. + @ r9 currently points to the memory location just above the auto saved + @ xPSR. + @ The cpu might automatically 8-byte align the stack. Bit 9 + @ of the saved xPSR specifies if stack aligning took place. In this case + @ another 32-bit value is included in the stack. + + tst r12, V7M_xPSR_FRAMEPTRALIGN + addne r9, r9, #4 + + @ store saved r12 using str to have a register to hold the base for stm + str r8, [sp, #S_IP] + add r8, sp, #S_SP + @ store r13-r15, xPSR + stmia r8!, {r9-r12} + @ store old_r0 + str r0, [r8] + .endm + + /* + * PENDSV and SVCALL are configured to have the same exception + * priorities. As a kernel thread runs at SVCALL execution priority it + * can never be preempted and so we will never have to return to a + * kernel thread here. + */ + .macro v7m_exception_slow_exit ret_r0 + cpsid i + ldr lr, =EXC_RET_THREADMODE_PROCESSSTACK + + @ read original r12, sp, lr, pc and xPSR + add r12, sp, #S_IP + ldmia r12, {r1-r5} + + @ an exception frame is always 8-byte aligned. To tell the hardware if + @ the sp to be restored is aligned or not set bit 9 of the saved xPSR + @ accordingly. + tst r2, #4 + subne r2, r2, #4 + orrne r5, V7M_xPSR_FRAMEPTRALIGN + biceq r5, V7M_xPSR_FRAMEPTRALIGN + + @ write basic exception frame + stmdb r2!, {r1, r3-r5} + ldmia sp, {r1, r3-r5} + .if \ret_r0 + stmdb r2!, {r0, r3-r5} + .else + stmdb r2!, {r1, r3-r5} + .endif + + @ restore process sp + msr psp, r2 + + @ restore original r4-r11 + ldmia sp!, {r0-r11} + + @ restore main sp + add sp, sp, #S_FRAME_SIZE-S_IP + + cpsie i + bx lr + .endm +#endif /* CONFIG_CPU_V7M */ + @ @ Store/load the USER SP and LR registers by switching to the SYS @ mode. Useful in Thumb-2 mode where "stm/ldm rd, {sp, lr}^" is not @@ -165,6 +276,18 @@ rfeia sp! .endm +#ifdef CONFIG_CPU_V7M + /* + * Note we don't need to do clrex here as clearing the local monitor is + * part of each exception entry and exit sequence. + */ + .macro restore_user_regs, fast = 0, offset = 0 + .if \offset + add sp, #\offset + .endif + v7m_exception_slow_exit ret_r0 = \fast + .endm +#else /* ifdef CONFIG_CPU_V7M */ .macro restore_user_regs, fast = 0, offset = 0 clrex @ clear the exclusive monitor mov r2, sp @@ -181,6 +304,7 @@ add sp, sp, #S_FRAME_SIZE - S_SP movs pc, lr @ return & move spsr_svc into cpsr .endm +#endif /* ifdef CONFIG_CPU_V7M / else */ .macro get_thread_info, rd mov \rd, sp |