| Message ID | 20171123164040.31551-2-steve.capper@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 23 November 2017 at 16:40, Steve Capper <steve.capper@arm.com> wrote: > Currently one resolves the location of the reserved_ttbr0 for PAN by > taking a positive offset from swapper_pg_dir. In a future patch we wish > to extend the swapper s.t. its size is determined at link time rather > than compile time, rendering SWAPPER_DIR_SIZE unsuitable for such a low > level calculation. > > In this patch we re-arrange the order of the linker script s.t. instead > one computes reserved_ttbr0 by subtracting RESERVED_TTBR0_SIZE from > swapper_pg_dir. > > Signed-off-by: Steve Capper <steve.capper@arm.com> > Acked-by: Mark Rutland <mark.rutland@arm.com> > --- > arch/arm64/include/asm/asm-uaccess.h | 6 +++--- > arch/arm64/include/asm/uaccess.h | 2 +- > arch/arm64/kernel/vmlinux.lds.S | 5 ++--- > 3 files changed, 6 insertions(+), 7 deletions(-) > > diff --git a/arch/arm64/include/asm/asm-uaccess.h b/arch/arm64/include/asm/asm-uaccess.h > index b3da6c886835..e09f02cd3e7a 100644 > --- a/arch/arm64/include/asm/asm-uaccess.h > +++ b/arch/arm64/include/asm/asm-uaccess.h > @@ -12,9 +12,9 @@ > */ > #ifdef CONFIG_ARM64_SW_TTBR0_PAN > .macro __uaccess_ttbr0_disable, tmp1 > - mrs \tmp1, ttbr1_el1 // swapper_pg_dir > - add \tmp1, \tmp1, #SWAPPER_DIR_SIZE // reserved_ttbr0 at the end of swapper_pg_dir > - msr ttbr0_el1, \tmp1 // set reserved TTBR0_EL1 > + mrs \tmp1, ttbr1_el1 // swapper_pg_dir > + sub \tmp1, \tmp1, #RESERVED_TTBR0_SIZE // reserved_ttbr0 just before swapper_pg_dir > + msr ttbr0_el1, \tmp1 // set reserved TTBR0_EL1 > isb > .endm > > diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h > index fc0f9eb66039..66170fd4b58f 100644 > --- a/arch/arm64/include/asm/uaccess.h > +++ b/arch/arm64/include/asm/uaccess.h > @@ -108,7 +108,7 @@ static inline void __uaccess_ttbr0_disable(void) > unsigned long ttbr; > > /* reserved_ttbr0 placed at the end of swapper_pg_dir */ You missed a comment here ^^^ > - ttbr = read_sysreg(ttbr1_el1) + SWAPPER_DIR_SIZE; > + ttbr = read_sysreg(ttbr1_el1) - RESERVED_TTBR0_SIZE; > write_sysreg(ttbr, ttbr0_el1); > isb(); > } > diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.lds.S > index 7da3e5c366a0..2a9475733e84 100644 > --- a/arch/arm64/kernel/vmlinux.lds.S > +++ b/arch/arm64/kernel/vmlinux.lds.S > @@ -206,13 +206,12 @@ SECTIONS > . = ALIGN(PAGE_SIZE); > idmap_pg_dir = .; > . += IDMAP_DIR_SIZE; > - swapper_pg_dir = .; > - . += SWAPPER_DIR_SIZE; > - > #ifdef CONFIG_ARM64_SW_TTBR0_PAN > reserved_ttbr0 = .; > . += RESERVED_TTBR0_SIZE; > #endif > + swapper_pg_dir = .; > + . += SWAPPER_DIR_SIZE; > > __pecoff_data_size = ABSOLUTE(. - __initdata_begin); > _end = .; With that fixed, Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
On Mon, Dec 04, 2017 at 02:13:38PM +0000, Ard Biesheuvel wrote: > On 23 November 2017 at 16:40, Steve Capper <steve.capper@arm.com> wrote: > > Currently one resolves the location of the reserved_ttbr0 for PAN by > > taking a positive offset from swapper_pg_dir. In a future patch we wish > > to extend the swapper s.t. its size is determined at link time rather > > than compile time, rendering SWAPPER_DIR_SIZE unsuitable for such a low > > level calculation. > > > > In this patch we re-arrange the order of the linker script s.t. instead > > one computes reserved_ttbr0 by subtracting RESERVED_TTBR0_SIZE from > > swapper_pg_dir. > > > > Signed-off-by: Steve Capper <steve.capper@arm.com> > > Acked-by: Mark Rutland <mark.rutland@arm.com> > > --- > > arch/arm64/include/asm/asm-uaccess.h | 6 +++--- > > arch/arm64/include/asm/uaccess.h | 2 +- > > arch/arm64/kernel/vmlinux.lds.S | 5 ++--- > > 3 files changed, 6 insertions(+), 7 deletions(-) > > > > diff --git a/arch/arm64/include/asm/asm-uaccess.h b/arch/arm64/include/asm/asm-uaccess.h > > index b3da6c886835..e09f02cd3e7a 100644 > > --- a/arch/arm64/include/asm/asm-uaccess.h > > +++ b/arch/arm64/include/asm/asm-uaccess.h > > @@ -12,9 +12,9 @@ > > */ > > #ifdef CONFIG_ARM64_SW_TTBR0_PAN > > .macro __uaccess_ttbr0_disable, tmp1 > > - mrs \tmp1, ttbr1_el1 // swapper_pg_dir > > - add \tmp1, \tmp1, #SWAPPER_DIR_SIZE // reserved_ttbr0 at the end of swapper_pg_dir > > - msr ttbr0_el1, \tmp1 // set reserved TTBR0_EL1 > > + mrs \tmp1, ttbr1_el1 // swapper_pg_dir > > + sub \tmp1, \tmp1, #RESERVED_TTBR0_SIZE // reserved_ttbr0 just before swapper_pg_dir > > + msr ttbr0_el1, \tmp1 // set reserved TTBR0_EL1 > > isb > > .endm > > > > diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h > > index fc0f9eb66039..66170fd4b58f 100644 > > --- a/arch/arm64/include/asm/uaccess.h > > +++ b/arch/arm64/include/asm/uaccess.h > > @@ -108,7 +108,7 @@ static inline void __uaccess_ttbr0_disable(void) > > unsigned long ttbr; > > > > /* reserved_ttbr0 placed at the end of swapper_pg_dir */ > > You missed a comment here ^^^ > Thanks, I will update this. > > - ttbr = read_sysreg(ttbr1_el1) + SWAPPER_DIR_SIZE; > > + ttbr = read_sysreg(ttbr1_el1) - RESERVED_TTBR0_SIZE; > > write_sysreg(ttbr, ttbr0_el1); > > isb(); > > } > > diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.lds.S > > index 7da3e5c366a0..2a9475733e84 100644 > > --- a/arch/arm64/kernel/vmlinux.lds.S > > +++ b/arch/arm64/kernel/vmlinux.lds.S > > @@ -206,13 +206,12 @@ SECTIONS > > . = ALIGN(PAGE_SIZE); > > idmap_pg_dir = .; > > . += IDMAP_DIR_SIZE; > > - swapper_pg_dir = .; > > - . += SWAPPER_DIR_SIZE; > > - > > #ifdef CONFIG_ARM64_SW_TTBR0_PAN > > reserved_ttbr0 = .; > > . += RESERVED_TTBR0_SIZE; > > #endif > > + swapper_pg_dir = .; > > + . += SWAPPER_DIR_SIZE; > > > > __pecoff_data_size = ABSOLUTE(. - __initdata_begin); > > _end = .; > > With that fixed, > > Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Thanks Ard! Cheers, -- Steve IMPORTANT NOTICE: The contents of this email and any attachments are confidential and may also be privileged. If you are not the intended recipient, please notify the sender immediately and do not disclose the contents to any other person, use it for any purpose, or store or copy the information in any medium. Thank you.
diff --git a/arch/arm64/include/asm/asm-uaccess.h b/arch/arm64/include/asm/asm-uaccess.h index b3da6c886835..e09f02cd3e7a 100644 --- a/arch/arm64/include/asm/asm-uaccess.h +++ b/arch/arm64/include/asm/asm-uaccess.h @@ -12,9 +12,9 @@ */ #ifdef CONFIG_ARM64_SW_TTBR0_PAN .macro __uaccess_ttbr0_disable, tmp1 - mrs \tmp1, ttbr1_el1 // swapper_pg_dir - add \tmp1, \tmp1, #SWAPPER_DIR_SIZE // reserved_ttbr0 at the end of swapper_pg_dir - msr ttbr0_el1, \tmp1 // set reserved TTBR0_EL1 + mrs \tmp1, ttbr1_el1 // swapper_pg_dir + sub \tmp1, \tmp1, #RESERVED_TTBR0_SIZE // reserved_ttbr0 just before swapper_pg_dir + msr ttbr0_el1, \tmp1 // set reserved TTBR0_EL1 isb .endm diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h index fc0f9eb66039..66170fd4b58f 100644 --- a/arch/arm64/include/asm/uaccess.h +++ b/arch/arm64/include/asm/uaccess.h @@ -108,7 +108,7 @@ static inline void __uaccess_ttbr0_disable(void) unsigned long ttbr; /* reserved_ttbr0 placed at the end of swapper_pg_dir */ - ttbr = read_sysreg(ttbr1_el1) + SWAPPER_DIR_SIZE; + ttbr = read_sysreg(ttbr1_el1) - RESERVED_TTBR0_SIZE; write_sysreg(ttbr, ttbr0_el1); isb(); } diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.lds.S index 7da3e5c366a0..2a9475733e84 100644 --- a/arch/arm64/kernel/vmlinux.lds.S +++ b/arch/arm64/kernel/vmlinux.lds.S @@ -206,13 +206,12 @@ SECTIONS . = ALIGN(PAGE_SIZE); idmap_pg_dir = .; . += IDMAP_DIR_SIZE; - swapper_pg_dir = .; - . += SWAPPER_DIR_SIZE; - #ifdef CONFIG_ARM64_SW_TTBR0_PAN reserved_ttbr0 = .; . += RESERVED_TTBR0_SIZE; #endif + swapper_pg_dir = .; + . += SWAPPER_DIR_SIZE; __pecoff_data_size = ABSOLUTE(. - __initdata_begin); _end = .;