On Thu, Sep 19, 2019 at 12:32:56PM +0300, Ard Biesheuvel wrote:
> On Wed, 18 Sep 2019 at 15:27, Baptiste Gerondeau
> <baptiste.gerond...@linaro.org> wrote:
> >
> > From: Baptiste GERONDEAU <bgerond...@gmail.com>
> >
> > RVCT and MSFT's ARM assembler share the same file syntax, but some
> > instructions use pre-UAL syntax that is not picked up
> > by MSFT's ARM assembler, this commit translates those instructions
> > into MSFT-buildable ones (subset of UAL/THUMB).
> >
> > Signed-off-by: Baptiste Gerondeau <baptiste.gerond...@linaro.org>
> > ---
> > ArmPkg/Library/ArmExceptionLib/Arm/ExceptionSupport.asm | 30
> > +++++++++++++++++-------------
> > ArmPkg/Library/ArmLib/Arm/ArmV7Support.asm | 6 ++++--
> > MdePkg/Library/BaseIoLibIntrinsic/Arm/ArmVirtMmio.asm | 18
> > +++++++++---------
> > 3 files changed, 30 insertions(+), 24 deletions(-)
> >
> > diff --git a/ArmPkg/Library/ArmExceptionLib/Arm/ExceptionSupport.asm
> > b/ArmPkg/Library/ArmExceptionLib/Arm/ExceptionSupport.asm
> > index aa0229d2e85f..880246bd6206 100644
> > --- a/ArmPkg/Library/ArmExceptionLib/Arm/ExceptionSupport.asm
> > +++ b/ArmPkg/Library/ArmExceptionLib/Arm/ExceptionSupport.asm
> > @@ -90,7 +90,7 @@ Fiq
> > ResetEntry
> > srsfd #0x13! ; Store return state on SVC stack
> > ; We are already in SVC mode
> > - stmfd SP!,{LR} ; Store the link register for the
> > current mode
> > + push {LR} ; Store the link register for the
> > current mode
> > sub SP,SP,#0x20 ; Save space for SP, LR, PC, IFAR -
> > CPSR
> > stmfd SP!,{R0-R12} ; Store the register state
> >
> > @@ -102,7 +102,7 @@ UndefinedInstructionEntry
> > sub LR, LR, #4 ; Only -2 for Thumb, adjust in
> > CommonExceptionEntry
> > srsfd #0x13! ; Store return state on SVC stack
> > cps #0x13 ; Switch to SVC for common stack
> > - stmfd SP!,{LR} ; Store the link register for the
> > current mode
> > + push {LR} ; Store the link register for the
> > current mode
> > sub SP,SP,#0x20 ; Save space for SP, LR, PC, IFAR -
> > CPSR
> > stmfd SP!,{R0-R12} ; Store the register state
> >
> > @@ -113,7 +113,7 @@ UndefinedInstructionEntry
> > SoftwareInterruptEntry
> > srsfd #0x13! ; Store return state on SVC stack
> > ; We are already in SVC mode
> > - stmfd SP!,{LR} ; Store the link register for the
> > current mode
> > + push {LR} ; Store the link register for the
> > current mode
> > sub SP,SP,#0x20 ; Save space for SP, LR, PC, IFAR -
> > CPSR
> > stmfd SP!,{R0-R12} ; Store the register state
> >
> > @@ -125,7 +125,7 @@ PrefetchAbortEntry
> > sub LR,LR,#4
> > srsfd #0x13! ; Store return state on SVC stack
> > cps #0x13 ; Switch to SVC for common stack
> > - stmfd SP!,{LR} ; Store the link register for the
> > current mode
> > + push {LR} ; Store the link register for the
> > current mode
> > sub SP,SP,#0x20 ; Save space for SP, LR, PC, IFAR -
> > CPSR
> > stmfd SP!,{R0-R12} ; Store the register state
> >
> > @@ -137,7 +137,7 @@ DataAbortEntry
> > sub LR,LR,#8
> > srsfd #0x13! ; Store return state on SVC stack
> > cps #0x13 ; Switch to SVC for common stack
> > - stmfd SP!,{LR} ; Store the link register for the
> > current mode
> > + push {LR} ; Store the link register for the
> > current mode
> > sub SP,SP,#0x20 ; Save space for SP, LR, PC, IFAR -
> > CPSR
> > stmfd SP!,{R0-R12} ; Store the register state
> >
> > @@ -148,7 +148,7 @@ DataAbortEntry
> > ReservedExceptionEntry
> > srsfd #0x13! ; Store return state on SVC stack
> > cps #0x13 ; Switch to SVC for common stack
> > - stmfd SP!,{LR} ; Store the link register for the
> > current mode
> > + push {LR} ; Store the link register for the
> > current mode
> > sub SP,SP,#0x20 ; Save space for SP, LR, PC, IFAR -
> > CPSR
> > stmfd SP!,{R0-R12} ; Store the register state
> >
> > @@ -160,7 +160,7 @@ IrqEntry
> > sub LR,LR,#4
> > srsfd #0x13! ; Store return state on SVC stack
> > cps #0x13 ; Switch to SVC for common stack
> > - stmfd SP!,{LR} ; Store the link register for the
> > current mode
> > + push {LR} ; Store the link register for the
> > current mode
> > sub SP,SP,#0x20 ; Save space for SP, LR, PC, IFAR -
> > CPSR
> > stmfd SP!,{R0-R12} ; Store the register state
> >
> > @@ -172,7 +172,7 @@ FiqEntry
> > sub LR,LR,#4
> > srsfd #0x13! ; Store return state on SVC stack
> > cps #0x13 ; Switch to SVC for common stack
> > - stmfd SP!,{LR} ; Store the link register for the
> > current mode
> > + push {LR} ; Store the link register for the
> > current mode
> > sub SP,SP,#0x20 ; Save space for SP, LR, PC, IFAR -
> > CPSR
> > stmfd SP!,{R0-R12} ; Store the register state
> > ; Since we have already switch to
> > SVC R8_fiq - R12_fiq
> > @@ -213,9 +213,11 @@ AsmCommonExceptionEntry
> > and R3, R1, #0x1f ; Check CPSR to see if User or System
> > Mode
> > cmp R3, #0x1f ; if ((CPSR == 0x10) || (CPSR == 0x1f))
> > cmpne R3, #0x10 ;
> > - stmeqed R2, {lr}^ ; save unbanked lr
> > + mrseq R8, lr_usr ; save unbanked lr to R8
> > + streq R2, [R8] ; make R2 point to R8
> > ; else
> > - stmneed R2, {lr} ; save SVC lr
> > + mrsne R8, lr_svc ; save SVC lr to R8
> > + strne R2, [R8] ; make R2 point to R8
> >
>
> Can you make this str unconditional, and drop the former?
Yeah, that would be an improvement.
> >
> > ldr R5, [SP, #0x58] ; PC is the LR pushed by srsfd
> > @@ -280,15 +282,17 @@ CommonCExceptionHandler (
> > and R1, R1, #0x1f ; Check to see if User or System Mode
> > cmp R1, #0x1f ; if ((CPSR == 0x10) || (CPSR == 0x1f))
> > cmpne R1, #0x10 ;
> > - ldmeqed R2, {lr}^ ; restore unbanked lr
> > + ldreq R8, [R2] ; load sys/usr lr from R2 pointer
> > + msreq lr_usr, R8 ; restore unbanked lr
> > ; else
> > - ldmneed R3, {lr} ; restore SVC lr, via ldmfd SP!, {LR}
> > + ldrne R8, [R3] ; load SVC lr from R3 pointer
> > + msrne lr_svc, R8 ; restore SVC lr, via ldmfd SP!, {LR}
> >
> > ldmfd SP!,{R0-R12} ; Restore general purpose registers
> > ; Exception handler can not change SP
> >
> > add SP,SP,#0x20 ; Clear out the remaining stack space
> > - ldmfd SP!,{LR} ; restore the link register for this
> > context
> > + pop {LR} ; restore the link register for this
> > context
> > rfefd SP! ; return from exception via srsfd
> > stack slot
> >
> > END
> > diff --git a/ArmPkg/Library/ArmLib/Arm/ArmV7Support.asm
> > b/ArmPkg/Library/ArmLib/Arm/ArmV7Support.asm
> > index 3146c2b52181..724306399e6c 100644
> > --- a/ArmPkg/Library/ArmLib/Arm/ArmV7Support.asm
> > +++ b/ArmPkg/Library/ArmLib/Arm/ArmV7Support.asm
> > @@ -200,8 +200,10 @@ Loop2
> > mov R9, R4 ; R9 working copy of the max way size
> > (right aligned)
> >
> > Loop3
> > - orr R0, R10, R9, LSL R5 ; factor in the way number and cache
> > number into R11
> > - orr R0, R0, R7, LSL R2 ; factor in the index number
> > + lsl R8, R9, R5
> > + orr R0, R10, R8 ; factor in the way number and cache number
> > + lsl R8, R7, R2
> > + orr R0, R0, R8 ; factor in the index number
> >
>
> What's wrong with this code?
Inline barrel shifter is only available in A32, not T32 (and VS seems
to love T32).
/
Leif
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