| Message ID | 20180824165820.32620-3-julien.grall@arm.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | xen/arm: SMCCC fixup and improvement | expand |
Hi, On 24.08.18 19:58, Julien Grall wrote: > From: Marc Zyngier <marc.zyngier@arm.com> > > If someone has the silly idea to write something along those lines: > > extern u64 foo(void); > > void bar(struct arm_smccc_res *res) > { > arm_smccc_1_1_smc(0xbad, foo(), res); > } > > they are in for a surprise, as this gets compiled as: > > 0000000000000588 <bar>: > 588: a9be7bfd stp x29, x30, [sp, #-32]! > 58c: 910003fd mov x29, sp > 590: f9000bf3 str x19, [sp, #16] > 594: aa0003f3 mov x19, x0 > 598: aa1e03e0 mov x0, x30 > 59c: 94000000 bl 0 <_mcount> > 5a0: 94000000 bl 0 <foo> > 5a4: aa0003e1 mov x1, x0 > 5a8: d4000003 smc #0x0 > 5ac: b4000073 cbz x19, 5b8 <bar+0x30> > 5b0: a9000660 stp x0, x1, [x19] > 5b4: a9010e62 stp x2, x3, [x19, #16] > 5b8: f9400bf3 ldr x19, [sp, #16] > 5bc: a8c27bfd ldp x29, x30, [sp], #32 > 5c0: d65f03c0 ret > 5c4: d503201f nop > > The call to foo "overwrites" the x0 register for the return value, > and we end up calling the wrong secure service. > > A solution is to evaluate all the parameters before assigning > anything to specific registers, leading to the expected result: > > 0000000000000588 <bar>: > 588: a9be7bfd stp x29, x30, [sp, #-32]! > 58c: 910003fd mov x29, sp > 590: f9000bf3 str x19, [sp, #16] > 594: aa0003f3 mov x19, x0 > 598: aa1e03e0 mov x0, x30 > 59c: 94000000 bl 0 <_mcount> > 5a0: 94000000 bl 0 <foo> > 5a4: aa0003e1 mov x1, x0 > 5a8: d28175a0 mov x0, #0xbad > 5ac: d4000003 smc #0x0 > 5b0: b4000073 cbz x19, 5bc <bar+0x34> > 5b4: a9000660 stp x0, x1, [x19] > 5b8: a9010e62 stp x2, x3, [x19, #16] > 5bc: f9400bf3 ldr x19, [sp, #16] > 5c0: a8c27bfd ldp x29, x30, [sp], #32 > 5c4: d65f03c0 ret > > Reported-by: Stefano Stabellini <stefanos@xilinx.com> > Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Volodymyr Babchuk <volodymr_babchuk@epam.com> > --- > xen/include/asm-arm/smccc.h | 30 ++++++++++++++++++++---------- > 1 file changed, 20 insertions(+), 10 deletions(-) > > diff --git a/xen/include/asm-arm/smccc.h b/xen/include/asm-arm/smccc.h > index a31d67a1de..648bef28bd 100644 > --- a/xen/include/asm-arm/smccc.h > +++ b/xen/include/asm-arm/smccc.h > @@ -125,41 +125,51 @@ struct arm_smccc_res { > register unsigned long r3 asm("r3") > > #define __declare_arg_1(a0, a1, res) \ > + typeof(a1) __a1 = a1; \ > struct arm_smccc_res *___res = res; \ > register unsigned long r0 asm("r0") = (uint32_t)a0;\ > - register unsigned long r1 asm("r1") = a1; \ > + register unsigned long r1 asm("r1") = __a1; \ > register unsigned long r2 asm("r2"); \ > register unsigned long r3 asm("r3") > > #define __declare_arg_2(a0, a1, a2, res) \ > + typeof(a1) __a1 = a1; \ > + typeof(a2) __a2 = a2; \ > struct arm_smccc_res *___res = res; \ > register unsigned long r0 asm("r0") = (uint32_t)a0;\ > - register unsigned long r1 asm("r1") = a1; \ > - register unsigned long r2 asm("r2") = a2; \ > + register unsigned long r1 asm("r1") = __a1; \ > + register unsigned long r2 asm("r2") = __a2; \ > register unsigned long r3 asm("r3") > > #define __declare_arg_3(a0, a1, a2, a3, res) \ > + typeof(a1) __a1 = a1; \ > + typeof(a2) __a2 = a2; \ > + typeof(a3) __a3 = a3; \ > struct arm_smccc_res *___res = res; \ > register unsigned long r0 asm("r0") = (uint32_t)a0;\ > - register unsigned long r1 asm("r1") = a1; \ > - register unsigned long r2 asm("r2") = a2; \ > - register unsigned long r3 asm("r3") = a3 > + register unsigned long r1 asm("r1") = __a1; \ > + register unsigned long r2 asm("r2") = __a2; \ > + register unsigned long r3 asm("r3") = __a3 > > #define __declare_arg_4(a0, a1, a2, a3, a4, res) \ > + typeof(a4) __a4 = a4; \ > __declare_arg_3(a0, a1, a2, a3, res); \ > - register unsigned long r4 asm("r4") = a4 > + register unsigned long r4 asm("r4") = __a4 > > #define __declare_arg_5(a0, a1, a2, a3, a4, a5, res) \ > + typeof(a5) __a5 = a5; \ > __declare_arg_4(a0, a1, a2, a3, a4, res); \ > - register typeof(a5) r5 asm("r5") = a5 > + register typeof(a5) r5 asm("r5") = __a5 > > #define __declare_arg_6(a0, a1, a2, a3, a4, a5, a6, res) \ > + typeof(a6) __a6 = a6; \ > __declare_arg_5(a0, a1, a2, a3, a4, a5, res); \ > - register typeof(a6) r6 asm("r6") = a6 > + register typeof(a6) r6 asm("r6") = __a6 > > #define __declare_arg_7(a0, a1, a2, a3, a4, a5, a6, a7, res) \ > + typeof(a7) __a7 = a7; \ > __declare_arg_6(a0, a1, a2, a3, a4, a5, a6, res); \ > - register typeof(a7) r7 asm("r7") = a7 > + register typeof(a7) r7 asm("r7") = __a7 > > #define ___declare_args(count, ...) __declare_arg_ ## count(__VA_ARGS__) > #define __declare_args(count, ...) ___declare_args(count, __VA_ARGS__) >
diff --git a/xen/include/asm-arm/smccc.h b/xen/include/asm-arm/smccc.h index a31d67a1de..648bef28bd 100644 --- a/xen/include/asm-arm/smccc.h +++ b/xen/include/asm-arm/smccc.h @@ -125,41 +125,51 @@ struct arm_smccc_res { register unsigned long r3 asm("r3") #define __declare_arg_1(a0, a1, res) \ + typeof(a1) __a1 = a1; \ struct arm_smccc_res *___res = res; \ register unsigned long r0 asm("r0") = (uint32_t)a0;\ - register unsigned long r1 asm("r1") = a1; \ + register unsigned long r1 asm("r1") = __a1; \ register unsigned long r2 asm("r2"); \ register unsigned long r3 asm("r3") #define __declare_arg_2(a0, a1, a2, res) \ + typeof(a1) __a1 = a1; \ + typeof(a2) __a2 = a2; \ struct arm_smccc_res *___res = res; \ register unsigned long r0 asm("r0") = (uint32_t)a0;\ - register unsigned long r1 asm("r1") = a1; \ - register unsigned long r2 asm("r2") = a2; \ + register unsigned long r1 asm("r1") = __a1; \ + register unsigned long r2 asm("r2") = __a2; \ register unsigned long r3 asm("r3") #define __declare_arg_3(a0, a1, a2, a3, res) \ + typeof(a1) __a1 = a1; \ + typeof(a2) __a2 = a2; \ + typeof(a3) __a3 = a3; \ struct arm_smccc_res *___res = res; \ register unsigned long r0 asm("r0") = (uint32_t)a0;\ - register unsigned long r1 asm("r1") = a1; \ - register unsigned long r2 asm("r2") = a2; \ - register unsigned long r3 asm("r3") = a3 + register unsigned long r1 asm("r1") = __a1; \ + register unsigned long r2 asm("r2") = __a2; \ + register unsigned long r3 asm("r3") = __a3 #define __declare_arg_4(a0, a1, a2, a3, a4, res) \ + typeof(a4) __a4 = a4; \ __declare_arg_3(a0, a1, a2, a3, res); \ - register unsigned long r4 asm("r4") = a4 + register unsigned long r4 asm("r4") = __a4 #define __declare_arg_5(a0, a1, a2, a3, a4, a5, res) \ + typeof(a5) __a5 = a5; \ __declare_arg_4(a0, a1, a2, a3, a4, res); \ - register typeof(a5) r5 asm("r5") = a5 + register typeof(a5) r5 asm("r5") = __a5 #define __declare_arg_6(a0, a1, a2, a3, a4, a5, a6, res) \ + typeof(a6) __a6 = a6; \ __declare_arg_5(a0, a1, a2, a3, a4, a5, res); \ - register typeof(a6) r6 asm("r6") = a6 + register typeof(a6) r6 asm("r6") = __a6 #define __declare_arg_7(a0, a1, a2, a3, a4, a5, a6, a7, res) \ + typeof(a7) __a7 = a7; \ __declare_arg_6(a0, a1, a2, a3, a4, a5, a6, res); \ - register typeof(a7) r7 asm("r7") = a7 + register typeof(a7) r7 asm("r7") = __a7 #define ___declare_args(count, ...) __declare_arg_ ## count(__VA_ARGS__) #define __declare_args(count, ...) ___declare_args(count, __VA_ARGS__)