在 2022/6/17 16:24, Mark Rutland 写道:
On Sat, May 28, 2022 at 06:50:50AM +0000, Tong Tiangen wrote:Currnetly, the extable type used by __arch_copy_from/to_user() is EX_TYPE_FIXUP. In fact, It is more clearly to use meaningful EX_TYPE_UACCESS_*. Suggested-by: Mark Rutland <mark.rutland@xxxxxxx> Signed-off-by: Tong Tiangen <tongtiangen@xxxxxxxxxx> --- arch/arm64/include/asm/asm-extable.h | 8 ++++++++ arch/arm64/include/asm/asm-uaccess.h | 12 ++++++------ 2 files changed, 14 insertions(+), 6 deletions(-) diff --git a/arch/arm64/include/asm/asm-extable.h b/arch/arm64/include/asm/asm-extable.h index 56ebe183e78b..9c94ac1f082c 100644 --- a/arch/arm64/include/asm/asm-extable.h +++ b/arch/arm64/include/asm/asm-extable.h @@ -28,6 +28,14 @@ __ASM_EXTABLE_RAW(\insn, \fixup, EX_TYPE_FIXUP, 0) .endm+/*+ * Create an exception table entry for uaccess `insn`, which will branch to `fixup` + * when an unhandled fault is taken. + * ex->data = ~0 means both reg_err and reg_zero is set to wzr(x31). + */ + .macro _asm_extable_uaccess, insn, fixup + __ASM_EXTABLE_RAW(\insn, \fixup, EX_TYPE_UACCESS_ERR_ZERO, ~0) + .endmI'm not too keen on using `~0` here, since that also sets other bits in the data field, and its somewhat opaque. How painful is it to generate the data fields as with the C version of this macro, so that we can pass in wzr explciitly for the two sub-fields? Other than that, this looks good to me. Thanks, Mark.
ok, will fix next version. Thanks, Tong.
/* * Create an exception table entry for `insn` if `fixup` is provided. Otherwise * do nothing. diff --git a/arch/arm64/include/asm/asm-uaccess.h b/arch/arm64/include/asm/asm-uaccess.h index 0557af834e03..75b211c98dea 100644 --- a/arch/arm64/include/asm/asm-uaccess.h +++ b/arch/arm64/include/asm/asm-uaccess.h @@ -61,7 +61,7 @@ alternative_else_nop_endif#define USER(l, x...) \9999: x; \ - _asm_extable 9999b, l + _asm_extable_uaccess 9999b, l/** Generate the assembly for LDTR/STTR with exception table entries. @@ -73,8 +73,8 @@ alternative_else_nop_endif 8889: ldtr \reg2, [\addr, #8]; add \addr, \addr, \post_inc;- _asm_extable 8888b,\l;- _asm_extable 8889b,\l; + _asm_extable_uaccess 8888b, \l; + _asm_extable_uaccess 8889b, \l; .endm.macro user_stp l, reg1, reg2, addr, post_inc@@ -82,14 +82,14 @@ alternative_else_nop_endif 8889: sttr \reg2, [\addr, #8]; add \addr, \addr, \post_inc;- _asm_extable 8888b,\l;- _asm_extable 8889b,\l; + _asm_extable_uaccess 8888b,\l; + _asm_extable_uaccess 8889b,\l; .endm.macro user_ldst l, inst, reg, addr, post_inc8888: \inst \reg, [\addr]; add \addr, \addr, \post_inc;- _asm_extable 8888b,\l;+ _asm_extable_uaccess 8888b, \l; .endm #endif -- 2.25.1.
