[Xen-devel] [PATCH 2/2] xen: arm: traps: correct cond

[Peng Fan <Peng.Fan@xxxxxxxxxxxxx>]

From "G6.2.29 CPSR, Current Program Status Register" of Aarch64 ARM
and "B1.3.3 Program Status Registers (PSRs)" of ARMv7-A ARM:
"
IT[7:5] holds the base condition for the IT block. The base condition is
        the top 3 bits of the condition code specified by the first
        condition field of the IT instruction.
IT[4:0] encodes the size of the IT block, which is the number of
        instructions that are to be conditionally executed, by the
        position of the least significant 1 in this field. It also
        encodes the value of the least significant bit of the condition
        code for each instruction in the block.
"

So should be "cond = ( it >> 5 );" but not "cond = ( it >> 4 );"

Signed-off-by: Peng Fan <Peng.Fan@xxxxxxxxxxxxx>
Cc: Ian Campbell <ian.campbell@xxxxxxxxxx>
Cc: Stefano Stabellini <stefano.stabellini@xxxxxxxxxx>
Cc: Julien Grall <julien.grall@xxxxxxxxxx>
---
 xen/arch/arm/traps.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/xen/arch/arm/traps.c b/xen/arch/arm/traps.c
index 2e2b1f2..b2879b7 100644
--- a/xen/arch/arm/traps.c
+++ b/xen/arch/arm/traps.c
@@ -1561,8 +1561,8 @@ static int check_conditional_instr(struct cpu_user_regs 
*regs,
         if ( it == 0 )
             return 1;
 
-        /* The cond for this instruction works out as the top 4 bits. */
-        cond = ( it >> 4 );
+        /* The cond for this instruction works out as the top 3 bits. */
+        cond = ( it >> 5 );
     }
 
     cpsr_cond = cpsr >> 28;
-- 
1.8.4



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