On Wed, Sep 05, 2012 at 04:32:01PM +0800, Guodong Xu wrote:
> Turn on CCI snoops. Data abort exception is captured and handled
> for implementations where CCI is not integrated.
This may work for now, but it's potentially fragile. We may get
platform variants where there is some different peripheral at 0x2c090000.
The cleanest solution would be to examine the device tree, but
unfortunately there are no mature bindings for the CCI yet.
We should fix that in parallel, but in the meantime we could add boot
arguments to provide the CCI base address and identify which master
port(s) to enable snooping for.
--cci=0x2c090000:3,4
or
--board=<boardname>
where we use <boardname> to select which extra board setup code we
need to run.
Cheers
---Dave
>
> Signed-off-by: Guodong Xu <guodong.xu@xxxxxxxxxx>
> ---
> Makefile | 6 +++++-
> boot.S | 41 ++++++++++++++++++++++++++++++++++++++---
> model.lds.S | 4 ++++
> secure.S | 28 ++++++++++++++++++++++++++++
> 4 files changed, 75 insertions(+), 4 deletions(-)
> create mode 100644 secure.S
>
> diff --git a/Makefile b/Makefile
> index 995fd8f..f3cdee3 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -15,9 +15,10 @@ endif
>
> LIBFDTOBJS = libfdt/fdt.o libfdt/fdt_ro.o libfdt/fdt_wip.o \
> libfdt/fdt_sw.o libfdt/fdt_rw.o libfdt/fdt_strerror.o
> +SECURE = secure.S
> MONITOR = monitor.S
> BOOTLOADER = boot.S
> -OBJS = boot.o c_start.o monitor.o semihosting.o string.o semi_loader.o $(LIBFDTOBJS)
> +OBJS = boot.o c_start.o monitor.o secure.o semihosting.o string.o semi_loader.o $(LIBFDTOBJS)
> KERNEL = uImage
>
> IMAGE = linux-system.axf
> @@ -53,6 +54,9 @@ $(SEMIIMG): $(OBJS) modelsemi.lds
> boot.o: $(BOOTLOADER)
> $(CC) $(CPPFLAGS) -DKCMD='$(KCMD)' -c -o $@ $<
>
> +secure.o: $(SECURE)
> + $(CC) $(CPPFLAGS) -c -o $@ $<
> +
> monitor.o: $(MONITOR)
> $(CC) $(CPPFLAGS) -c -o $@ $<
>
> diff --git a/boot.S b/boot.S
> index 61cd93f..a5f3f20 100644
> --- a/boot.S
> +++ b/boot.S
> @@ -67,14 +67,49 @@ start:
> mov r0, #0xf0000000
> mcr p15, 0, r0, c12, c0, 1 @ Monitor vector base address
>
> - @ Set up hvbar so hvc comes back here.
> + @ Load secure.S, Secure Vector Table
> + add r0, r0, #0x4000 @ SEC_OFFSET
> + mcr p15, 0, r0, c12, c0, 0 @ VBR Secure vector base address
> +
> + @ Check CPU nr again
> + mrc p15, 0, r0, c0, c0, 5 @ MPIDR (ARMv7 only)
> + bfc r0, #24, #8 @ CPU number and cluster
> + cmp r0, #0 @ primary CPU?
> + bne 4f
> +
> + @ primary CPU
> +
> + @
> + @ Turn on CCI snoops
> + @
> + ldr r4, =0x2c090000
> + ldr r3, [r4, #0xc] @ status reg
> + @
> + @ If CCI doesn't exist, access to it can cause data abort exception.
> + @ Data abort handling routine marks r4
> + @
> + nop
> + nop
> + cmp r4, #0xba
> + beq 4f @ no CCI, skip
> +
> + mov r3, #3
> + mov r5, #0x4000 @ A15
> + str r3, [r4, r5]
> + mov r5, #0x5000 @ A7
> + str r3, [r4, r5]
> +3: ldr r3, [r4, #0xc] @ status reg
> + tst r3, #1
> + bne 3b
> +
> +4: @ Set up hvbar so hvc comes back here.
> ldr r0, =vectors
> mov r7, #0xfffffff0
> smc #0 @ Set HVBAR
>
> @ We can't call hvc from secure mode, so drop down first.
> mov r7, #0xffffffff
> - smc #0 @ Change to NS-mode
> + smc #0 @ Change to NS-mode
>
> @ This is how we enter hyp mode, for booting the next stage.
> hvc #0
> @@ -93,7 +128,7 @@ vectors:
> into_hyp_mode:
> @ Check CPU nr again
> mrc p15, 0, r0, c0, c0, 5 @ MPIDR (ARMv7 only)
> - and r0, r0, #15 @ CPU number
> + bfc r0, #24, #8 @ CPU number and cluster
> cmp r0, #0 @ primary CPU?
> beq 2f
>
> diff --git a/model.lds.S b/model.lds.S
> index 07fae8c..aa7d3b8 100644
> --- a/model.lds.S
> +++ b/model.lds.S
> @@ -22,6 +22,7 @@ INPUT(./uImage)
>
> PHYS_OFFSET = 0x80000000;
> MON_OFFSET = 0xf0000000;
> +SEC_OFFSET = 0xf0004000;
> STACKTOP = 0xff000000;
>
>
> @@ -49,6 +50,9 @@ SECTIONS
> . = MON_OFFSET;
> .monitor : { monitor.o }
>
> + . = SEC_OFFSET;
> + .secure : { secure.o }
> +
> /* Put most of the actual boot loader code up in high memory
> * where it won't get overwritten by kernel, initrd or atags.
> */
> diff --git a/secure.S b/secure.S
> new file mode 100644
> index 0000000..681e212
> --- /dev/null
> +++ b/secure.S
> @@ -0,0 +1,28 @@
> +/*
> + * secure.S - simple monitor code to switch to NS state before executing kernel
> + *
> + * Copyright (C) 2012 Linaro - http://www.linaro.org. All rights reserved.
> + * Guodong Xu <guodong.xu@xxxxxxxxxx>
> + *
> + * Use of this source code is governed by a BSD-style license that can be
> + * found in the LICENSE.txt file.
> + */
> +
> +#.syntax unified
> + .section secure, "x"
> +
> + .word 0 /* reset */
> + .word 0 /* undefined instruction */
> + .word 0 /* supervisor call */
> + .word 0 /* prefetch abort */
> + b 1f /* data abort */
> + .word 0 /* not useed */
> + .word 0 /* IRQ */
> + .word 0 /* FIQ */
> +
> +1: @
> + @ data abort handling
> + @
> + /* do nothing, just return */
> + mov r4, #0xba @ mark r4
> + subs pc, lr, #0 @ return where from
> --
> 1.7.4.1
>
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