From mboxrd@z Thu Jan 1 00:00:00 1970 From: mark.rutland@arm.com (Mark Rutland) Date: Tue, 26 Aug 2014 16:22:04 +0100 Subject: [PATCH] Arm64: convert soft_restart() to assembly code In-Reply-To: References: <1407847365-10873-1-git-send-email-achandran@mvista.com> <1408123221.22761.38.camel@smoke> <20140815182157.GD21908@leverpostej> <1408128799.22761.47.camel@smoke> <20140818160253.GB3302@leverpostej> Message-ID: <20140826152204.GC4078@leverpostej> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org > Hi Mark, Hi Arun, > Please Ignore my previous mail. I think this version of sample > implementation is simple and better. Please give your comments. If you wish to have this reviewed in any depth, please: - Base your patches on mainline, or at the very least provide a pointer to the branch the patch is based upon. - Test that this functions with and without CONFIG_KVM. - Post this as an RFC PATCH, complete with a rationale (as previously discussed). - For later revisions, please label the patches with a version and give adequate delay between postings to allow for review. I've given some comments below, but please post proper patches in future. > ########### > diff --git a/arch/arm64/include/asm/proc-fns.h > b/arch/arm64/include/asm/proc-fns.h > index ddbc3f5..40d3360 100644 > --- a/arch/arm64/include/asm/proc-fns.h > +++ b/arch/arm64/include/asm/proc-fns.h > @@ -31,7 +31,7 @@ struct cpu_suspend_ctx; > extern void cpu_cache_off(void); > extern void cpu_do_idle(void); > extern void cpu_do_switch_mm(unsigned long pgd_phys, struct mm_struct *mm); > -extern void cpu_reset(unsigned long addr) __attribute__((noreturn)); > +extern void cpu_reset(unsigned long addr, unsigned long boot_mode) > __attribute__((noreturn)); > extern void cpu_soft_restart(phys_addr_t cpu_reset, unsigned long > addr) __attribute__((noreturn)); > extern void cpu_do_suspend(struct cpu_suspend_ctx *ptr); > extern u64 cpu_do_resume(phys_addr_t ptr, u64 idmap_ttbr); > diff --git a/arch/arm64/include/asm/virt.h b/arch/arm64/include/asm/virt.h > index 215ad46..3976737 100644 > --- a/arch/arm64/include/asm/virt.h > +++ b/arch/arm64/include/asm/virt.h > @@ -34,6 +34,7 @@ > */ > extern u32 __boot_cpu_mode[2]; > > +void __hyp_func_call(phys_addr_t func, ...); > void __hyp_set_vectors(phys_addr_t phys_vector_base); > phys_addr_t __hyp_get_vectors(void); > > diff --git a/arch/arm64/kernel/hyp-stub.S b/arch/arm64/kernel/hyp-stub.S > index a272f33..82c2b0d 100644 > --- a/arch/arm64/kernel/hyp-stub.S > +++ b/arch/arm64/kernel/hyp-stub.S > @@ -53,14 +53,12 @@ ENDPROC(__hyp_stub_vectors) > .align 11 > > el1_sync: > - mrs x1, esr_el2 > - lsr x1, x1, #26 > - cmp x1, #0x16 > + mrs x19, esr_el2 > + lsr x19, x19, #26 > + cmp x19, #0x16 > b.ne 2f // Not an HVC trap > - cbz x0, 1f > - msr vbar_el2, x0 // Set vbar_el2 > - b 2f > -1: mrs x0, vbar_el2 // Return vbar_el2 > + > +1: blr x0 // Jump to the function You need to stash the orignal lr, or we can't return from __hyp_call_func. > 2: eret > ENDPROC(el1_sync) > > @@ -101,10 +99,17 @@ ENDPROC(\label) > */ > > ENTRY(__hyp_get_vectors) > - mov x0, xzr > - // fall through > -ENTRY(__hyp_set_vectors) > - hvc #0 > + mrs x0, vbar_el2 // Return vbar_el2 > ret > ENDPROC(__hyp_get_vectors) > + > +ENTRY(__hyp_set_vectors) > + msr vbar_el2, x1 > + ret > ENDPROC(__hyp_set_vectors) > + > +/* Call a function @x0 */ > +ENTRY(__hyp_func_call) > + hvc #0 > + ret > +ENDPROC(__hyp_func_call) These will be called at EL1, so this breaks KVM. > diff --git a/arch/arm64/mm/proc.S b/arch/arm64/mm/proc.S > index 3cb6dec..e68f42e 100644 > --- a/arch/arm64/mm/proc.S > +++ b/arch/arm64/mm/proc.S > @@ -25,6 +25,7 @@ > #include > #include > #include > +#include > > #include "proc-macros.S" > > @@ -69,19 +70,26 @@ ENDPROC(cpu_cache_off) > */ > .align 5 > ENTRY(cpu_reset) > - mrs x1, sctlr_el1 > - bic x1, x1, #1 > - msr sctlr_el1, x1 // disable the MMU > + mrs x2, sctlr_el1 > + bic x2, x2, #1 > + msr sctlr_el1, x2 // disable the MMU > isb > #if defined(CONFIG_SMP) > /* bl secondary_shutdown */ > #endif > + sub w1, w1, #BOOT_CPU_MODE_EL2 > + cbz w1, __hyp_func_call > ret x0 > ENDPROC(cpu_reset) Please base your patches on mainline (or if you need the fixed-up soft_restart, the arm64 devel branch). I thought we'd shot down the idea of the secondary_shutdown call. > ENTRY(cpu_soft_restart) > + ldr x3, =__boot_cpu_mode > + add x3, x3, #4 > + ldr w2, [x3] > + > mov x19, x0 > mov x20, x1 > + mov w21, w2 > > /* Turn D-cache off */ > bl cpu_cache_off > @@ -89,6 +97,7 @@ ENTRY(cpu_soft_restart) > bl flush_cache_all > > mov x0, x20 > + mov w1, w21 > ret x19 > ENDPROC(cpu_soft_restart) > ######### > > I have implemented __hyp_func_call; other userscan > make use of it to call __hyp_set_vectors/__hyp_get_vectors The callers of those functions _must_ be updated in this patch to use the new hypercall mechanism. Thanks, Mark.