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Message-Id: <20220124174744.1054712-6-ardb@kernel.org>
Date: Mon, 24 Jan 2022 18:47:17 +0100
From: Ard Biesheuvel <ardb@...nel.org>
To: linux@...linux.org.uk, linux-arm-kernel@...ts.infradead.org
Cc: linux-hardening@...r.kernel.org, Ard Biesheuvel <ardb@...nel.org>,
Nicolas Pitre <nico@...xnic.net>,
Arnd Bergmann <arnd@...db.de>,
Kees Cook <keescook@...omium.org>,
Keith Packard <keithpac@...zon.com>,
Linus Walleij <linus.walleij@...aro.org>,
Nick Desaulniers <ndesaulniers@...gle.com>,
Tony Lindgren <tony@...mide.com>,
Marc Zyngier <maz@...nel.org>,
Vladimir Murzin <vladimir.murzin@....com>,
Jesse Taube <mr.bossman075@...il.com>
Subject: [PATCH v5 05/32] ARM: iop32x: use GENERIC_IRQ_MULTI_HANDLER
From: Arnd Bergmann <arnd@...db.de>
iop32x uses the entry-macro.S file for both the IRQ entry and for
hooking into the arch_ret_to_user code path. This is done because the
cp6 registers have to be enabled before accessing any of the interrupt
controller registers but have to be disabled when running in user space.
There is also a lazy-enable logic in cp6.c, but during a hardirq, we
know it has to be enabled.
Both the cp6-enable code and the code to read the IRQ status can be
lifted into the normal generic_handle_arch_irq() path, but the
cp6-disable code has to remain in the user return code. As nothing
other than iop32x uses this hook, just open-code it there with an
ifdef for the platform that can eventually be removed when iop32x
has reached the end of its life.
The cp6-enable path in the IRQ entry has an extra cp_wait barrier that
the trap version does not have, but it is harmless to do it in both
cases to simplify the logic here at the cost of a few extra cycles
for the trap.
Signed-off-by: Arnd Bergmann <arnd@...db.de>
Signed-off-by: Ard Biesheuvel <ardb@...nel.org>
Tested-by: Marc Zyngier <maz@...nel.org>
Tested-by: Vladimir Murzin <vladimir.murzin@....com> # ARMv7M
---
arch/arm/Kconfig | 5 +---
arch/arm/kernel/entry-common.S | 16 +++++-----
arch/arm/mach-iop32x/cp6.c | 10 ++++++-
arch/arm/mach-iop32x/include/mach/entry-macro.S | 31 --------------------
arch/arm/mach-iop32x/iop3xx.h | 1 +
arch/arm/mach-iop32x/irq.c | 23 +++++++++++++++
6 files changed, 43 insertions(+), 43 deletions(-)
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index bef5085f2ce7..ac2f88ce0b9a 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -226,9 +226,6 @@ config GENERIC_ISA_DMA
config FIQ
bool
-config NEED_RET_TO_USER
- bool
-
config ARCH_MTD_XIP
bool
@@ -370,9 +367,9 @@ config ARCH_IOP32X
bool "IOP32x-based"
depends on MMU
select CPU_XSCALE
+ select GENERIC_IRQ_MULTI_HANDLER
select GPIO_IOP
select GPIOLIB
- select NEED_RET_TO_USER
select FORCE_PCI
select PLAT_IOP
help
diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S
index ac86c34682bb..c928d6b04cce 100644
--- a/arch/arm/kernel/entry-common.S
+++ b/arch/arm/kernel/entry-common.S
@@ -16,12 +16,14 @@
.equ NR_syscalls, __NR_syscalls
-#ifdef CONFIG_NEED_RET_TO_USER
-#include <mach/entry-macro.S>
-#else
- .macro arch_ret_to_user, tmp1, tmp2
- .endm
+ .macro arch_ret_to_user, tmp
+#ifdef CONFIG_ARCH_IOP32X
+ mrc p15, 0, \tmp, c15, c1, 0
+ tst \tmp, #(1 << 6)
+ bicne \tmp, \tmp, #(1 << 6)
+ mcrne p15, 0, \tmp, c15, c1, 0 @ Disable cp6 access
#endif
+ .endm
#include "entry-header.S"
@@ -55,7 +57,7 @@ __ret_fast_syscall:
/* perform architecture specific actions before user return */
- arch_ret_to_user r1, lr
+ arch_ret_to_user r1
restore_user_regs fast = 1, offset = S_OFF
UNWIND(.fnend )
@@ -128,7 +130,7 @@ no_work_pending:
asm_trace_hardirqs_on save = 0
/* perform architecture specific actions before user return */
- arch_ret_to_user r1, lr
+ arch_ret_to_user r1
ct_user_enter save = 0
restore_user_regs fast = 0, offset = 0
diff --git a/arch/arm/mach-iop32x/cp6.c b/arch/arm/mach-iop32x/cp6.c
index ec74b07fb7e3..2882674a1c39 100644
--- a/arch/arm/mach-iop32x/cp6.c
+++ b/arch/arm/mach-iop32x/cp6.c
@@ -7,7 +7,7 @@
#include <asm/traps.h>
#include <asm/ptrace.h>
-static int cp6_trap(struct pt_regs *regs, unsigned int instr)
+void iop_enable_cp6(void)
{
u32 temp;
@@ -16,7 +16,15 @@ static int cp6_trap(struct pt_regs *regs, unsigned int instr)
"mrc p15, 0, %0, c15, c1, 0\n\t"
"orr %0, %0, #(1 << 6)\n\t"
"mcr p15, 0, %0, c15, c1, 0\n\t"
+ "mrc p15, 0, %0, c15, c1, 0\n\t"
+ "mov %0, %0\n\t"
+ "sub pc, pc, #4 @ cp_wait\n\t"
: "=r"(temp));
+}
+
+static int cp6_trap(struct pt_regs *regs, unsigned int instr)
+{
+ iop_enable_cp6();
return 0;
}
diff --git a/arch/arm/mach-iop32x/include/mach/entry-macro.S b/arch/arm/mach-iop32x/include/mach/entry-macro.S
deleted file mode 100644
index 341e5d9a6616..000000000000
--- a/arch/arm/mach-iop32x/include/mach/entry-macro.S
+++ /dev/null
@@ -1,31 +0,0 @@
-/*
- * arch/arm/mach-iop32x/include/mach/entry-macro.S
- *
- * Low-level IRQ helper macros for IOP32x-based platforms
- *
- * This file is licensed under the terms of the GNU General Public
- * License version 2. This program is licensed "as is" without any
- * warranty of any kind, whether express or implied.
- */
- .macro get_irqnr_preamble, base, tmp
- mrc p15, 0, \tmp, c15, c1, 0
- orr \tmp, \tmp, #(1 << 6)
- mcr p15, 0, \tmp, c15, c1, 0 @ Enable cp6 access
- mrc p15, 0, \tmp, c15, c1, 0
- mov \tmp, \tmp
- sub pc, pc, #4 @ cp_wait
- .endm
-
- .macro get_irqnr_and_base, irqnr, irqstat, base, tmp
- mrc p6, 0, \irqstat, c8, c0, 0 @ Read IINTSRC
- cmp \irqstat, #0
- clzne \irqnr, \irqstat
- rsbne \irqnr, \irqnr, #32
- .endm
-
- .macro arch_ret_to_user, tmp1, tmp2
- mrc p15, 0, \tmp1, c15, c1, 0
- ands \tmp2, \tmp1, #(1 << 6)
- bicne \tmp1, \tmp1, #(1 << 6)
- mcrne p15, 0, \tmp1, c15, c1, 0 @ Disable cp6 access
- .endm
diff --git a/arch/arm/mach-iop32x/iop3xx.h b/arch/arm/mach-iop32x/iop3xx.h
index 46b4b34a4ad2..a6ec7ebadb35 100644
--- a/arch/arm/mach-iop32x/iop3xx.h
+++ b/arch/arm/mach-iop32x/iop3xx.h
@@ -225,6 +225,7 @@ extern int iop3xx_get_init_atu(void);
#include <linux/reboot.h>
void iop3xx_map_io(void);
+void iop_enable_cp6(void);
void iop_init_cp6_handler(void);
void iop_init_time(unsigned long tickrate);
void iop3xx_restart(enum reboot_mode, const char *);
diff --git a/arch/arm/mach-iop32x/irq.c b/arch/arm/mach-iop32x/irq.c
index d1e8824cbd82..6dca7e97d81f 100644
--- a/arch/arm/mach-iop32x/irq.c
+++ b/arch/arm/mach-iop32x/irq.c
@@ -29,6 +29,15 @@ static void intstr_write(u32 val)
asm volatile("mcr p6, 0, %0, c4, c0, 0" : : "r" (val));
}
+static u32 iintsrc_read(void)
+{
+ int irq;
+
+ asm volatile("mrc p6, 0, %0, c8, c0, 0" : "=r" (irq));
+
+ return irq;
+}
+
static void
iop32x_irq_mask(struct irq_data *d)
{
@@ -50,11 +59,25 @@ struct irq_chip ext_chip = {
.irq_unmask = iop32x_irq_unmask,
};
+static void iop_handle_irq(struct pt_regs *regs)
+{
+ u32 mask;
+
+ iop_enable_cp6();
+
+ do {
+ mask = iintsrc_read();
+ if (mask)
+ generic_handle_irq(fls(mask));
+ } while (mask);
+}
+
void __init iop32x_init_irq(void)
{
int i;
iop_init_cp6_handler();
+ set_handle_irq(iop_handle_irq);
intctl_write(0);
intstr_write(0);
--
2.30.2
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