From: James Morse <james.morse@arm.com> To: linux-arm-kernel@lists.infradead.org Cc: Will Deacon <will.deacon@arm.com>, Sudeep Holla <sudeep.holla@arm.com>, Geoff Levand <geoff@infradead.org>, Catalin Marinas <catalin.marinas@arm.com>, Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>, Mark Rutland <mark.rutland@arm.com>, AKASHI Takahiro <takahiro.akashi@linaro.org>, Marc Zyngier <marc.zyngier@arm.com>, "Rafael J . Wysocki" <rjw@rjwysocki.net>, Pavel Machek <pavel@ucw.cz>, linux-pm@vger.kernel.org, James Morse <james.morse@arm.com> Subject: [PATCH v5 04/15] arm64: Add new hcall HVC_CALL_FUNC Date: Tue, 16 Feb 2016 15:49:16 +0000 [thread overview] Message-ID: <1455637767-31561-5-git-send-email-james.morse@arm.com> (raw) In-Reply-To: <1455637767-31561-1-git-send-email-james.morse@arm.com> From: Geoff Levand <geoff@infradead.org> Add the new hcall HVC_CALL_FUNC that allows execution of a function at EL2. During CPU reset the CPU must be brought to the exception level it had on entry to the kernel. The HVC_CALL_FUNC hcall will provide the mechanism needed for this exception level switch. To allow the HVC_CALL_FUNC exception vector to work without a stack, which is needed to support an hcall at CPU reset, this implementation uses register x18 to store the link register across the caller provided function. This dictates that the caller provided function must preserve the contents of register x18. Signed-off-by: Geoff Levand <geoff@infradead.org> [Renumbered labels in el1_sync()] Signed-off-by: James Morse <james.morse@arm.com> --- This patch comes from v13 of kexec arch/arm64/include/asm/virt.h | 13 +++++++++++++ arch/arm64/kernel/hyp-stub.S | 19 +++++++++++++++---- 2 files changed, 28 insertions(+), 4 deletions(-) diff --git a/arch/arm64/include/asm/virt.h b/arch/arm64/include/asm/virt.h index eb10368c329e..30700961f28c 100644 --- a/arch/arm64/include/asm/virt.h +++ b/arch/arm64/include/asm/virt.h @@ -45,6 +45,19 @@ #define HVC_SET_VECTORS 2 +/* + * HVC_CALL_FUNC - Execute a function at EL2. + * + * @x0: Physical address of the function to be executed. + * @x1: Passed as the first argument to the function. + * @x2: Passed as the second argument to the function. + * @x3: Passed as the third argument to the function. + * + * The called function must preserve the contents of register x18. + */ + +#define HVC_CALL_FUNC 3 + #define BOOT_CPU_MODE_EL1 (0xe11) #define BOOT_CPU_MODE_EL2 (0xe12) diff --git a/arch/arm64/kernel/hyp-stub.S b/arch/arm64/kernel/hyp-stub.S index 017ab519aaf1..cfacfe55e3ef 100644 --- a/arch/arm64/kernel/hyp-stub.S +++ b/arch/arm64/kernel/hyp-stub.S @@ -59,18 +59,29 @@ el1_sync: and x18, x18, #ESR_ELx_ISS_MASK cmp x17, #ESR_ELx_EC_HVC64 - b.ne 2f // Not an HVC trap + b.ne 9f // Not an HVC trap cmp x18, #HVC_GET_VECTORS b.ne 1f mrs x0, vbar_el2 - b 2f + b 9f 1: cmp x18, #HVC_SET_VECTORS b.ne 2f msr vbar_el2, x0 - -2: eret + b 9f + +2: cmp x18, #HVC_CALL_FUNC + b.ne 9f + mov x18, lr + mov lr, x0 + mov x0, x1 + mov x1, x2 + mov x2, x3 + blr lr + mov lr, x18 + +9: eret ENDPROC(el1_sync) .macro invalid_vector label -- 2.6.2
WARNING: multiple messages have this Message-ID (diff)
From: james.morse@arm.com (James Morse) To: linux-arm-kernel@lists.infradead.org Subject: [PATCH v5 04/15] arm64: Add new hcall HVC_CALL_FUNC Date: Tue, 16 Feb 2016 15:49:16 +0000 [thread overview] Message-ID: <1455637767-31561-5-git-send-email-james.morse@arm.com> (raw) In-Reply-To: <1455637767-31561-1-git-send-email-james.morse@arm.com> From: Geoff Levand <geoff@infradead.org> Add the new hcall HVC_CALL_FUNC that allows execution of a function at EL2. During CPU reset the CPU must be brought to the exception level it had on entry to the kernel. The HVC_CALL_FUNC hcall will provide the mechanism needed for this exception level switch. To allow the HVC_CALL_FUNC exception vector to work without a stack, which is needed to support an hcall at CPU reset, this implementation uses register x18 to store the link register across the caller provided function. This dictates that the caller provided function must preserve the contents of register x18. Signed-off-by: Geoff Levand <geoff@infradead.org> [Renumbered labels in el1_sync()] Signed-off-by: James Morse <james.morse@arm.com> --- This patch comes from v13 of kexec arch/arm64/include/asm/virt.h | 13 +++++++++++++ arch/arm64/kernel/hyp-stub.S | 19 +++++++++++++++---- 2 files changed, 28 insertions(+), 4 deletions(-) diff --git a/arch/arm64/include/asm/virt.h b/arch/arm64/include/asm/virt.h index eb10368c329e..30700961f28c 100644 --- a/arch/arm64/include/asm/virt.h +++ b/arch/arm64/include/asm/virt.h @@ -45,6 +45,19 @@ #define HVC_SET_VECTORS 2 +/* + * HVC_CALL_FUNC - Execute a function at EL2. + * + * @x0: Physical address of the function to be executed. + * @x1: Passed as the first argument to the function. + * @x2: Passed as the second argument to the function. + * @x3: Passed as the third argument to the function. + * + * The called function must preserve the contents of register x18. + */ + +#define HVC_CALL_FUNC 3 + #define BOOT_CPU_MODE_EL1 (0xe11) #define BOOT_CPU_MODE_EL2 (0xe12) diff --git a/arch/arm64/kernel/hyp-stub.S b/arch/arm64/kernel/hyp-stub.S index 017ab519aaf1..cfacfe55e3ef 100644 --- a/arch/arm64/kernel/hyp-stub.S +++ b/arch/arm64/kernel/hyp-stub.S @@ -59,18 +59,29 @@ el1_sync: and x18, x18, #ESR_ELx_ISS_MASK cmp x17, #ESR_ELx_EC_HVC64 - b.ne 2f // Not an HVC trap + b.ne 9f // Not an HVC trap cmp x18, #HVC_GET_VECTORS b.ne 1f mrs x0, vbar_el2 - b 2f + b 9f 1: cmp x18, #HVC_SET_VECTORS b.ne 2f msr vbar_el2, x0 - -2: eret + b 9f + +2: cmp x18, #HVC_CALL_FUNC + b.ne 9f + mov x18, lr + mov lr, x0 + mov x0, x1 + mov x1, x2 + mov x2, x3 + blr lr + mov lr, x18 + +9: eret ENDPROC(el1_sync) .macro invalid_vector label -- 2.6.2
next prev parent reply other threads:[~2016-02-16 15:51 UTC|newest] Thread overview: 62+ messages / expand[flat|nested] mbox.gz Atom feed top 2016-02-16 15:49 [PATCH v5 00/15] arm64: kernel: Add support for hibernate/suspend-to-disk James Morse 2016-02-16 15:49 ` James Morse 2016-02-16 15:49 ` [PATCH v5 01/15] arm64: Fold proc-macros.S into assembler.h James Morse 2016-02-16 15:49 ` James Morse 2016-02-16 15:49 ` [PATCH v5 02/15] arm64: Cleanup SCTLR flags James Morse 2016-02-16 15:49 ` James Morse 2016-02-16 15:49 ` [PATCH v5 03/15] arm64: Convert hcalls to use HVC immediate value James Morse 2016-02-16 15:49 ` James Morse 2016-02-16 15:49 ` James Morse [this message] 2016-02-16 15:49 ` [PATCH v5 04/15] arm64: Add new hcall HVC_CALL_FUNC James Morse 2016-02-16 15:49 ` [PATCH v5 05/15] arm64: kvm: allows kvm cpu hotplug James Morse 2016-02-16 15:49 ` James Morse 2016-02-16 15:49 ` [PATCH v5 06/15] arm64: kernel: Rework finisher callback out of __cpu_suspend_enter() James Morse 2016-02-16 15:49 ` James Morse 2016-02-16 15:49 ` [PATCH v5 07/15] arm64: Change cpu_resume() to enable mmu early then access sleep_sp by va James Morse 2016-02-16 15:49 ` James Morse 2016-02-18 18:26 ` Lorenzo Pieralisi 2016-02-18 18:26 ` Lorenzo Pieralisi 2016-02-19 16:20 ` James Morse 2016-02-19 16:20 ` James Morse 2016-02-19 16:43 ` Lorenzo Pieralisi 2016-02-19 16:43 ` Lorenzo Pieralisi 2016-02-16 15:49 ` [PATCH v5 08/15] arm64: kernel: Include _AC definition in page.h James Morse 2016-02-16 15:49 ` James Morse 2016-02-16 15:49 ` [PATCH v5 09/15] arm64: Promote KERNEL_START/KERNEL_END definitions to a header file James Morse 2016-02-16 15:49 ` James Morse 2016-02-16 15:49 ` [PATCH v5 10/15] arm64: Add new asm macro copy_page James Morse 2016-02-16 15:49 ` James Morse 2016-02-16 15:49 ` [PATCH v5 11/15] arm64: head.S: Change the register el2_setup() returns its result in x0 James Morse 2016-02-16 15:49 ` James Morse 2016-02-18 11:41 ` Lorenzo Pieralisi 2016-02-18 11:41 ` Lorenzo Pieralisi 2016-02-18 11:45 ` Pavel Machek 2016-02-18 11:45 ` Pavel Machek 2016-02-18 11:57 ` James Morse 2016-02-18 11:57 ` James Morse 2016-02-16 15:49 ` [PATCH v5 12/15] arm64: head.S: el2_setup() to accept sctlr_el1 as an argument James Morse 2016-02-16 15:49 ` James Morse 2016-02-16 15:49 ` [PATCH v5 13/15] PM / Hibernate: Call flush_icache_range() on pages restored in-place James Morse 2016-02-16 15:49 ` James Morse 2016-02-16 19:27 ` Rafael J. Wysocki 2016-02-16 19:27 ` Rafael J. Wysocki 2016-02-16 15:49 ` [PATCH v5 14/15] arm64: kernel: Add support for hibernate/suspend-to-disk James Morse 2016-02-16 15:49 ` James Morse 2016-02-18 17:13 ` Lorenzo Pieralisi 2016-02-18 17:13 ` Lorenzo Pieralisi 2016-02-16 15:49 ` [PATCH v5 15/15] arm64: hibernate: Prevent resume from a different kernel version James Morse 2016-02-16 15:49 ` James Morse 2016-02-16 20:15 ` Pavel Machek 2016-02-16 20:15 ` Pavel Machek 2016-02-17 2:20 ` Chen, Yu C 2016-02-17 2:20 ` Chen, Yu C 2016-02-18 12:00 ` James Morse 2016-02-18 12:00 ` James Morse 2016-02-20 19:16 ` Chen, Yu C 2016-02-20 19:16 ` Chen, Yu C 2016-02-20 19:57 ` Pavel Machek 2016-02-20 19:57 ` Pavel Machek 2016-02-21 9:04 ` Chen, Yu C 2016-02-21 9:04 ` Chen, Yu C 2016-02-23 18:29 ` [PATCH v5 00/15] arm64: kernel: Add support for hibernate/suspend-to-disk Kevin Hilman 2016-02-23 18:29 ` Kevin Hilman
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