On 11/28/18 15:33, Ard Biesheuvel wrote: > Add a helper function that returns the maximum physical address space > size as supported by the current CPU. > > Contributed-under: TianoCore Contribution Agreement 1.1 > Signed-off-by: Ard Biesheuvel <ard.biesheu...@linaro.org> > --- > ArmPkg/Include/Library/ArmLib.h | 6 ++++++ > ArmPkg/Library/ArmLib/AArch64/ArmLibSupport.S | 17 +++++++++++++++++ > ArmPkg/Library/ArmLib/Arm/ArmLibSupport.S | 8 ++++++++ > ArmPkg/Library/ArmLib/Arm/ArmLibSupport.asm | 8 ++++++++ > 4 files changed, 39 insertions(+) > > diff --git a/ArmPkg/Include/Library/ArmLib.h b/ArmPkg/Include/Library/ArmLib.h > index ffda50e9d767..9a804c15fdb6 100644 > --- a/ArmPkg/Include/Library/ArmLib.h > +++ b/ArmPkg/Include/Library/ArmLib.h > @@ -733,4 +733,10 @@ ArmWriteCntvOff ( > UINT64 Val > ); > > +UINTN > +EFIAPI > +ArmGetPhysicalAddressBits ( > + VOID > + ); > + > #endif // __ARM_LIB__ > diff --git a/ArmPkg/Library/ArmLib/AArch64/ArmLibSupport.S > b/ArmPkg/Library/ArmLib/AArch64/ArmLibSupport.S > index 1ef2f61f5979..b7173e00b039 100644 > --- a/ArmPkg/Library/ArmLib/AArch64/ArmLibSupport.S > +++ b/ArmPkg/Library/ArmLib/AArch64/ArmLibSupport.S > @@ -196,4 +196,21 @@ ASM_FUNC(ArmWriteSctlr) > 3:msr sctlr_el3, x0 > 4:ret > > +ASM_FUNC(ArmGetPhysicalAddressBits) > + mrs x0, id_aa64mmfr0_el1 > + adr x1, .LPARanges > + and x0, x0, #0xf > + ldrb w0, [x1, x0] > + ret > + > +// > +// Bits 0..3 of the AA64MFR0_EL1 system register encode the size of the > +// physical address space support on this CPU: > +// 0 == 32 bits, 1 == 36 bits, etc etc > +// 7 and up are reserved > +// > +.LPARanges: > + .byte 32, 36, 40, 42, 44, 48, 52, 0 > + .byte 0, 0, 0, 0, 0, 0, 0, 0 > + > ASM_FUNCTION_REMOVE_IF_UNREFERENCED > diff --git a/ArmPkg/Library/ArmLib/Arm/ArmLibSupport.S > b/ArmPkg/Library/ArmLib/Arm/ArmLibSupport.S > index f2a517671f0a..0e9f9d0453e4 100644 > --- a/ArmPkg/Library/ArmLib/Arm/ArmLibSupport.S > +++ b/ArmPkg/Library/ArmLib/Arm/ArmLibSupport.S > @@ -165,4 +165,12 @@ ASM_FUNC(ArmWriteCpuActlr) > isb > bx lr > > +ASM_FUNC (ArmGetPhysicalAddressBits) > + mrc p15, 0, r0, c0, c1, 4 // MMFR0 > + and r0, r0, #0xf // VMSA [3:0] > + cmp r0, #5 // >= 5 implies LPAE support > + movlt r0, #32 // 32 bits if no LPAE > + movge r0, #40 // 40 bits if LPAE > + bx lr > + > ASM_FUNCTION_REMOVE_IF_UNREFERENCED > diff --git a/ArmPkg/Library/ArmLib/Arm/ArmLibSupport.asm > b/ArmPkg/Library/ArmLib/Arm/ArmLibSupport.asm > index 219140c22b13..3eb52875971d 100644 > --- a/ArmPkg/Library/ArmLib/Arm/ArmLibSupport.asm > +++ b/ArmPkg/Library/ArmLib/Arm/ArmLibSupport.asm > @@ -169,4 +169,12 @@ > isb > bx lr > > + RVCT_ASM_EXPORT ArmGetPhysicalAddressBits > + mrc p15, 0, r0, c0, c1, 4 ; MMFR0 > + and r0, r0, #0xf ; VMSA [3:0] > + cmp r0, #5 ; >= 5 implies LPAE support > + movlt r0, #32 ; 32 bits if no LPAE > + movge r0, #40 ; 40 bits if LPAE > + bx lr > + > END >
I didn't review the assembly code, but formally, the patch looks OK to me. Acked-by: Laszlo Ersek <ler...@redhat.com> _______________________________________________ edk2-devel mailing list edk2-devel@lists.01.org https://lists.01.org/mailman/listinfo/edk2-devel
