From: Will Deacon <will.deacon@arm.com>
To: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org, catalin.marinas@arm.com,
mark.rutland@arm.com, ard.biesheuvel@linaro.org,
sboyd@codeaurora.org, dave.hansen@linux.intel.com,
keescook@chromium.org, msalter@redhat.com, labbott@redhat.com,
tglx@linutronix.de, Will Deacon <will.deacon@arm.com>
Subject: [PATCH v2 13/18] arm64: entry: Hook up entry trampoline to exception vectors
Date: Thu, 30 Nov 2017 16:39:41 +0000 [thread overview]
Message-ID: <1512059986-21325-14-git-send-email-will.deacon@arm.com> (raw)
In-Reply-To: <1512059986-21325-1-git-send-email-will.deacon@arm.com>
Hook up the entry trampoline to our exception vectors so that all
exceptions from and returns to EL0 go via the trampoline, which swizzles
the vector base register accordingly. Transitioning to and from the
kernel clobbers x30, so we use tpidrro_el0 and far_el1 as scratch
registers for native tasks.
Signed-off-by: Will Deacon <will.deacon@arm.com>
---
arch/arm64/kernel/entry.S | 39 ++++++++++++++++++++++++++++++++++++---
1 file changed, 36 insertions(+), 3 deletions(-)
diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index 688e52f65a8d..99d105048663 100644
--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S
@@ -73,6 +73,17 @@
.macro kernel_ventry, el, label, regsize = 64
.align 7
+#ifdef CONFIG_UNMAP_KERNEL_AT_EL0
+ .if \el == 0
+ .if \regsize == 64
+ mrs x30, tpidrro_el0
+ msr tpidrro_el0, xzr
+ .else
+ mov x30, xzr
+ .endif
+ .endif
+#endif
+
sub sp, sp, #S_FRAME_SIZE
#ifdef CONFIG_VMAP_STACK
/*
@@ -119,6 +130,11 @@
b el\()\el\()_\label
.endm
+ .macro tramp_alias, dst, sym
+ mov_q \dst, TRAMP_VALIAS
+ add \dst, \dst, #(\sym - .entry.tramp.text)
+ .endm
+
.macro kernel_entry, el, regsize = 64
.if \regsize == 32
mov w0, w0 // zero upper 32 bits of x0
@@ -271,18 +287,20 @@ alternative_else_nop_endif
.if \el == 0
ldr x23, [sp, #S_SP] // load return stack pointer
msr sp_el0, x23
+ tst x22, #PSR_MODE32_BIT // native task?
+ b.eq 3f
+
#ifdef CONFIG_ARM64_ERRATUM_845719
alternative_if ARM64_WORKAROUND_845719
- tbz x22, #4, 1f
#ifdef CONFIG_PID_IN_CONTEXTIDR
mrs x29, contextidr_el1
msr contextidr_el1, x29
#else
msr contextidr_el1, xzr
#endif
-1:
alternative_else_nop_endif
#endif
+3:
.endif
msr elr_el1, x21 // set up the return data
@@ -304,7 +322,22 @@ alternative_else_nop_endif
ldp x28, x29, [sp, #16 * 14]
ldr lr, [sp, #S_LR]
add sp, sp, #S_FRAME_SIZE // restore sp
- eret // return to kernel
+
+#ifndef CONFIG_UNMAP_KERNEL_AT_EL0
+ eret
+#else
+ .if \el == 0
+ bne 4f
+ msr far_el1, x30
+ tramp_alias x30, tramp_exit_native
+ br x30
+4:
+ tramp_alias x30, tramp_exit_compat
+ br x30
+ .else
+ eret
+ .endif
+#endif
.endm
.macro irq_stack_entry
--
2.1.4
next prev parent reply other threads:[~2017-11-30 16:43 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-30 16:39 [PATCH v2 00/18] arm64: Unmap the kernel whilst running in userspace (KAISER) Will Deacon
2017-11-30 16:39 ` [PATCH v2 01/18] arm64: mm: Use non-global mappings for kernel space Will Deacon
2017-11-30 16:39 ` [PATCH v2 02/18] arm64: mm: Temporarily disable ARM64_SW_TTBR0_PAN Will Deacon
2017-11-30 16:39 ` [PATCH v2 03/18] arm64: mm: Move ASID from TTBR0 to TTBR1 Will Deacon
2017-11-30 17:36 ` Mark Rutland
2017-11-30 16:39 ` [PATCH v2 04/18] arm64: mm: Remove pre_ttbr0_update_workaround for Falkor erratum #E1003 Will Deacon
2017-11-30 16:39 ` [PATCH v2 05/18] arm64: mm: Rename post_ttbr0_update_workaround Will Deacon
2017-11-30 16:39 ` [PATCH v2 06/18] arm64: mm: Fix and re-enable ARM64_SW_TTBR0_PAN Will Deacon
2017-12-01 11:48 ` Mark Rutland
2017-11-30 16:39 ` [PATCH v2 07/18] arm64: mm: Allocate ASIDs in pairs Will Deacon
2017-11-30 16:39 ` [PATCH v2 08/18] arm64: mm: Add arm64_kernel_unmapped_at_el0 helper Will Deacon
2017-11-30 16:39 ` [PATCH v2 09/18] arm64: mm: Invalidate both kernel and user ASIDs when performing TLBI Will Deacon
2017-11-30 16:39 ` [PATCH v2 10/18] arm64: entry: Add exception trampoline page for exceptions from EL0 Will Deacon
2017-12-01 13:31 ` Mark Rutland
2017-12-06 10:25 ` Ard Biesheuvel
2017-11-30 16:39 ` [PATCH v2 11/18] arm64: mm: Map entry trampoline into trampoline and kernel page tables Will Deacon
2017-11-30 18:29 ` Mark Rutland
2017-11-30 16:39 ` [PATCH v2 12/18] arm64: entry: Explicitly pass exception level to kernel_ventry macro Will Deacon
2017-12-01 11:58 ` Mark Rutland
2017-12-01 17:51 ` Will Deacon
2017-12-01 18:00 ` Mark Rutland
2017-11-30 16:39 ` Will Deacon [this message]
2017-12-01 13:53 ` [PATCH v2 13/18] arm64: entry: Hook up entry trampoline to exception vectors Mark Rutland
2017-12-01 17:40 ` Will Deacon
2017-11-30 16:39 ` [PATCH v2 14/18] arm64: erratum: Work around Falkor erratum #E1003 in trampoline code Will Deacon
2017-11-30 17:06 ` Robin Murphy
2017-11-30 17:19 ` Will Deacon
2017-11-30 16:39 ` [PATCH v2 15/18] arm64: tls: Avoid unconditional zeroing of tpidrro_el0 for native tasks Will Deacon
2017-11-30 16:39 ` [PATCH v2 16/18] arm64: entry: Add fake CPU feature for unmapping the kernel at EL0 Will Deacon
2017-12-01 13:55 ` Mark Rutland
2017-11-30 16:39 ` [PATCH v2 17/18] arm64: Kconfig: Add CONFIG_UNMAP_KERNEL_AT_EL0 Will Deacon
2017-12-12 8:44 ` Geert Uytterhoeven
2017-12-12 10:28 ` Will Deacon
2017-11-30 16:39 ` [PATCH v2 18/18] perf: arm_spe: Disallow userspace profiling when arm_kernel_unmapped_at_el0() Will Deacon
2017-12-01 12:15 ` Mark Rutland
2017-12-01 16:49 ` Will Deacon
2017-12-01 16:26 ` Stephen Boyd
2017-12-01 14:04 ` [PATCH v2 00/18] arm64: Unmap the kernel whilst running in userspace (KAISER) Mark Rutland
2017-12-01 17:50 ` Will Deacon
2017-12-01 17:58 ` Mark Rutland
2017-12-01 18:02 ` Dave Hansen
2017-12-01 18:14 ` Will Deacon
2017-12-11 2:24 ` Shanker Donthineni
2017-12-04 23:47 ` Laura Abbott
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