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Re: [Qemu-devel] [Qemu-arm] [PATCH 09/13] armv7m: Implement M profile de
From: |
Philippe Mathieu-Daudé |
Subject: |
Re: [Qemu-devel] [Qemu-arm] [PATCH 09/13] armv7m: Implement M profile default memory map |
Date: |
Fri, 2 Jun 2017 02:10:19 -0300 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.8.0 |
Hi Peter,
On 05/30/2017 12:11 PM, Peter Maydell wrote:
On 30 May 2017 at 15:56, Philippe Mathieu-Daudé <address@hidden> wrote:
Hi Peter,
On 04/25/2017 09:07 AM, Peter Maydell wrote:
From: Michael Davidsaver <address@hidden>
Add support for the M profile default memory map which is used
if the MPU is not present or disabled.
The main differences in behaviour from implementing this
correctly are that we set the PAGE_EXEC attribute on
the right regions of memory, such that device regions
are not executable.
Signed-off-by: Michael Davidsaver <address@hidden>
[PMM: rephrased comment and commit message; don't mark
the flash memory region as not-writable]
"not-writable by system caches" maybe to clarify?
(Note that this is a comment describing something I
deleted from Michael's original patch.)
No, by 'not-writable' here I mean "not writeable by the CPU".
Ok!
Signed-off-by: Peter Maydell <address@hidden>
---
target/arm/helper.c | 35 ++++++++++++++++++++++++++---------
1 file changed, 26 insertions(+), 9 deletions(-)
diff --git a/target/arm/helper.c b/target/arm/helper.c
index 9e1ed1c..51662ad 100644
--- a/target/arm/helper.c
+++ b/target/arm/helper.c
@@ -8129,18 +8129,35 @@ static inline void
get_phys_addr_pmsav7_default(CPUARMState *env,
ARMMMUIdx mmu_idx,
int32_t address, int
*prot)
{
- *prot = PAGE_READ | PAGE_WRITE;
- switch (address) {
- case 0xF0000000 ... 0xFFFFFFFF:
- if (regime_sctlr(env, mmu_idx) & SCTLR_V) { /* hivecs execing is
ok */
+ if (!arm_feature(env, ARM_FEATURE_M)) {
+ *prot = PAGE_READ | PAGE_WRITE;
+ switch (address) {
+ case 0xF0000000 ... 0xFFFFFFFF:
+ if (regime_sctlr(env, mmu_idx) & SCTLR_V) {
+ /* hivecs execing is ok */
+ *prot |= PAGE_EXEC;
+ }
+ break;
+ case 0x00000000 ... 0x7FFFFFFF:
*prot |= PAGE_EXEC;
I checked at Table B3-1 on the ARMv7-M Architecture Reference Manual I got
at https://static.docs.arm.com/ddi0403/e/DDI0403E_B_armv7m_arm.pdf and the
on-chip peripheral address space at 0x40000000 is eXecute Never.
This is the arm of the if() that deals with R profile, and R profile's
Oh I completely misunderstood that if() indeed. R and also A I suppose.
background region is completely different to M profile. (In any
case the patch shouldn't change the behaviour there.)
+ break;
+ }
+ } else {
+ /* Default system address map for M profile cores.
+ * The architecture specifies which regions are execute-never;
+ * at the MPU level no other checks are defined.
+ */
+ switch (address) {
+ case 0x00000000 ... 0x1fffffff: /* ROM */
+ case 0x20000000 ... 0x3fffffff: /* SRAM */
+ case 0x60000000 ... 0x7fffffff: /* RAM */
+ case 0x80000000 ... 0x9fffffff: /* RAM */
+ *prot = PAGE_READ | PAGE_WRITE | PAGE_EXEC;
+ break;
+ default: /* Peripheral, 2x Device, and System */
+ *prot = PAGE_READ | PAGE_WRITE;
This body is correct, however what do you think about using cases with
comments instead of 'default'? This would be clearer.
Yeah, we could do that. I think this is one of those cases where
I opted to go with how Michael had already written the code rather
than rewriting it.
/* Default system address map for M profile cores.
* The architecture specifies which regions are execute-never;
* at the MPU level no other checks are defined.
*/
switch (address) {
case 0x00000000 ... 0x1fffffff: /* ROM */
case 0x20000000 ... 0x3fffffff: /* SRAM */
case 0x60000000 ... 0x7fffffff: /* RAM */
case 0x80000000 ... 0x9fffffff: /* RAM */
*prot = PAGE_READ | PAGE_WRITE | PAGE_EXEC;
break;
case 0x40000000 ... 0x5fffffff: /* Peripheral */
case 0xa0000000 ... 0xbfffffff: /* Device */
case 0xc0000000 ... 0xdfffffff: /* Device */
case 0xe0000000 ... 0xffffffff: /* System */
*prot = PAGE_READ | PAGE_WRITE;
break;
default:
g_assert_not_reached();
}
would be the explicit version.
I see you added that before your pull request, thank!
For what it's worth:
Reviewed-by: Philippe Mathieu-Daudé <address@hidden>
}
- break;
- case 0x00000000 ... 0x7FFFFFFF:
- *prot |= PAGE_EXEC;
- break;
}
-
}
static bool get_phys_addr_pmsav7(CPUARMState *env, uint32_t address,
thanks
-- PMM
- Re: [Qemu-devel] [Qemu-arm] [PATCH 09/13] armv7m: Implement M profile default memory map,
Philippe Mathieu-Daudé <=