From: geoff@infradead.org (Geoff Levand) To: linux-arm-kernel@lists.infradead.org Subject: [PATCH 03/15] arm64: Add new hcall HVC_CALL_FUNC Date: Fri, 06 Nov 2015 19:14:36 +0000 [thread overview] Message-ID: <1bfd1af4061513bc07c38a778f1602bf4abe1e43.1446836442.git.geoff@infradead.org> (raw) In-Reply-To: <cover.1446836442.git.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> --- arch/arm64/include/asm/virt.h | 13 +++++++++++++ arch/arm64/kernel/hyp-stub.S | 13 ++++++++++++- 2 files changed, 25 insertions(+), 1 deletion(-) diff --git a/arch/arm64/include/asm/virt.h b/arch/arm64/include/asm/virt.h index eb10368..3070096 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 017ab519..e8febe9 100644 --- a/arch/arm64/kernel/hyp-stub.S +++ b/arch/arm64/kernel/hyp-stub.S @@ -67,8 +67,19 @@ el1_sync: b 2f 1: cmp x18, #HVC_SET_VECTORS - b.ne 2f + b.ne 1f msr vbar_el2, x0 + b 2f + +1: cmp x18, #HVC_CALL_FUNC + b.ne 2f + mov x18, lr + mov lr, x0 + mov x0, x1 + mov x1, x2 + mov x2, x3 + blr lr + mov lr, x18 2: eret ENDPROC(el1_sync) -- 2.5.0
WARNING: multiple messages have this Message-ID (diff)
From: Geoff Levand <geoff@infradead.org> To: Catalin Marinas <catalin.marinas@arm.com>, Will Deacon <will.deacon@arm.com> Cc: Mark Rutland <mark.rutland@arm.com>, marc.zyngier@arm.com, kexec@lists.infradead.org, AKASHI Takahiro <takahiro.akashi@linaro.org>, christoffer.dall@linaro.org, linux-arm-kernel@lists.infradead.org Subject: [PATCH 03/15] arm64: Add new hcall HVC_CALL_FUNC Date: Fri, 06 Nov 2015 19:14:36 +0000 [thread overview] Message-ID: <1bfd1af4061513bc07c38a778f1602bf4abe1e43.1446836442.git.geoff@infradead.org> (raw) In-Reply-To: <cover.1446836442.git.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> --- arch/arm64/include/asm/virt.h | 13 +++++++++++++ arch/arm64/kernel/hyp-stub.S | 13 ++++++++++++- 2 files changed, 25 insertions(+), 1 deletion(-) diff --git a/arch/arm64/include/asm/virt.h b/arch/arm64/include/asm/virt.h index eb10368..3070096 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 017ab519..e8febe9 100644 --- a/arch/arm64/kernel/hyp-stub.S +++ b/arch/arm64/kernel/hyp-stub.S @@ -67,8 +67,19 @@ el1_sync: b 2f 1: cmp x18, #HVC_SET_VECTORS - b.ne 2f + b.ne 1f msr vbar_el2, x0 + b 2f + +1: cmp x18, #HVC_CALL_FUNC + b.ne 2f + mov x18, lr + mov lr, x0 + mov x0, x1 + mov x1, x2 + mov x2, x3 + blr lr + mov lr, x18 2: eret ENDPROC(el1_sync) -- 2.5.0 _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec
next prev parent reply other threads:[~2015-11-06 19:14 UTC|newest] Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top 2015-11-06 19:14 [PATCH 00/15] arm64 kexec kernel patches v11 Geoff Levand 2015-11-06 19:14 ` Geoff Levand 2015-11-06 19:14 ` [PATCH 07/15] arm64/kexec: Add core kexec support Geoff Levand 2015-11-06 19:14 ` Geoff Levand 2015-11-06 19:14 ` [PATCH 01/15] arm64: Fold proc-macros.S into assembler.h Geoff Levand 2015-11-06 19:14 ` Geoff Levand 2015-11-06 19:14 ` [PATCH 09/15] arm64/kexec: Enable kexec in the arm64 defconfig Geoff Levand 2015-11-06 19:14 ` Geoff Levand 2015-11-06 19:14 ` [PATCH 04/15] arm64: kvm: allows kvm cpu hotplug Geoff Levand 2015-11-06 19:14 ` Geoff Levand 2015-11-06 19:14 ` [PATCH 05/15] arm64: Add back cpu_reset routines Geoff Levand 2015-11-06 19:14 ` Geoff Levand 2015-11-06 19:14 ` [PATCH 06/15] Revert "arm64: remove dead code" Geoff Levand 2015-11-06 19:14 ` Geoff Levand 2015-11-06 19:14 ` [PATCH 02/15] arm64: Convert hcalls to use HVC immediate value Geoff Levand 2015-11-06 19:14 ` Geoff Levand 2015-11-06 19:14 ` Geoff Levand [this message] 2015-11-06 19:14 ` [PATCH 03/15] arm64: Add new hcall HVC_CALL_FUNC Geoff Levand 2015-11-06 19:14 ` [PATCH 08/15] arm64/kexec: Add pr_devel output Geoff Levand 2015-11-06 19:14 ` Geoff Levand 2015-11-06 19:14 ` [PATCH 15/15] arm64: kdump: relax BUG_ON() if more than one cpus are still active Geoff Levand 2015-11-06 19:14 ` Geoff Levand 2015-11-06 19:14 ` [PATCH 10/15] arm64: kdump: reserve memory for crash dump kernel Geoff Levand 2015-11-06 19:14 ` Geoff Levand 2015-11-06 19:14 ` [PATCH 13/15] arm64: kdump: update a kernel doc Geoff Levand 2015-11-06 19:14 ` Geoff Levand 2015-11-06 19:14 ` [PATCH 12/15] arm64: kdump: add kdump support Geoff Levand 2015-11-06 19:14 ` Geoff Levand 2015-11-06 19:14 ` [PATCH 11/15] arm64: kdump: implement machine_crash_shutdown() Geoff Levand 2015-11-06 19:14 ` Geoff Levand 2015-11-10 1:23 ` AKASHI Takahiro 2015-11-10 1:23 ` AKASHI Takahiro 2015-11-10 9:54 ` Will Deacon 2015-11-10 9:54 ` Will Deacon 2015-11-06 19:14 ` [PATCH 14/15] arm64: kdump: enable kdump in the arm64 defconfig Geoff Levand 2015-11-06 19:14 ` Geoff Levand
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