On 28/10/2022 15:22, Ayan Kumar Halder wrote:
On 22/10/2022 12:03, Julien Grall wrote:
Hi Ayan,
Hi Julien,
I need a clarification.
Title: Xen doesn't emulate ICH_LR* (we don't expose them to the
guest). Instead Xen will use the registers and your patch provides
wrappers to use access the registers on 32-bit host.
On 21/10/2022 16:31, Ayan Kumar Halder wrote:
diff --git a/xen/arch/arm/include/asm/arm32/sysregs.h
b/xen/arch/arm/include/asm/arm32/sysregs.h
index 6841d5de43..f3b4dfbca8 100644
--- a/xen/arch/arm/include/asm/arm32/sysregs.h
+++ b/xen/arch/arm/include/asm/arm32/sysregs.h
@@ -62,9 +62,61 @@
#define READ_SYSREG(R...) READ_SYSREG32(R)
#define WRITE_SYSREG(V, R...) WRITE_SYSREG32(V, R)
+#define ICH_LR_REG(INDEX) ICH_LR ## INDEX ## _EL2
+#define ICH_LRC_REG(INDEX) ICH_LRC ## INDEX ## _EL2
+
+#define READ_SYSREG_LR(INDEX) ((((uint64_t) \
+ (READ_SYSREG(ICH_LRC_REG(INDEX)))) << 32) | \
+ (READ_SYSREG(ICH_LR_REG(INDEX))))
This is a bit dense to read. Also, we should use READ_CP64() when
dealing with arm32 only code. So how about (formatting will need to be
done):
#define READ_SYSREG_LR(INDEX) ({ \
uint32_t lrc_ = READ_CP64(ICH_LRC_REG(INDEX)); \
uint32_t lr_ = READ_CP64(ICH_LR_REG(INDEX)); \
\
I think this looks incorrect. These are read using 'mrc' so they should
be READ_CP32(). They are 32 bit registers.
That's my mistake. We should use...
However, READ_SYSREG is defined as READ_CP32(), so should we use
READ_CP32() or READ_SYSREG() ?
READ_CP32() instead of READ_SYSREG() for arm32 specific code. The latter
is only provided to avoid #ifdef in the common code.
Cheers,
--
Julien Grall
