From: Deepak Gupta <debug@rivosinc.com>
To: Alistair Francis <alistair23@gmail.com>
Cc: qemu-riscv@nongnu.org, qemu-devel@nongnu.org, palmer@dabbelt.com,
Alistair.Francis@wdc.com, laurent@vivier.eu, bmeng.cn@gmail.com,
liwei1518@gmail.com, dbarboza@ventanamicro.com,
zhiwei_liu@linux.alibaba.com, jim.shu@sifive.com,
andy.chiu@sifive.com, kito.cheng@sifive.com,
Richard Henderson <richard.henderson@linaro.org>
Subject: Re: [PATCH v11 13/20] target/riscv: mmu changes for zicfiss shadow stack protection
Date: Wed, 28 Aug 2024 17:17:19 -0700 [thread overview]
Message-ID: <Zs++D1WO/G1ntixu@debug.ba.rivosinc.com> (raw)
In-Reply-To: <CAKmqyKNVA3Y06824XbbsZ+7n2Ach==ah5m-28zxzCn-48En=9g@mail.gmail.com>
On Thu, Aug 29, 2024 at 10:03:04AM +1000, Alistair Francis wrote:
>On Thu, Aug 29, 2024 at 9:45 AM Deepak Gupta <debug@rivosinc.com> wrote:
>>
>> On Thu, Aug 29, 2024 at 09:29:49AM +1000, Alistair Francis wrote:
>> >On Thu, Aug 29, 2024 at 3:49 AM Deepak Gupta <debug@rivosinc.com> wrote:
>> >>
>> >> prot |= PAGE_WRITE;
>> >> }
>> >> - if (pte & PTE_X) {
>> >> + if (rwx & PTE_X) {
>> >> bool mxr = false;
>> >>
>> >> /*
>> >> @@ -1160,7 +1177,7 @@ restart:
>> >>
>> >> if (!((prot >> access_type) & 1)) {
>> >> /* Access check failed */
>> >> - return TRANSLATE_FAIL;
>> >> + return sstack_page ? TRANSLATE_PMP_FAIL : TRANSLATE_FAIL;
>> >
>> >Why is it a PMP error if it's a shadow stack page?
>>
>> A shadow stack page is readable by regular loads.
>> We are making sure of that in `case PTE_W` in above switch case.
>> But shadow stack page is not writeable via regular stores. And must raise
>> access fault. return code `TRANSLATE_PMP_FAIL` is translated to access fault
>> while raising fault.
>
>Ah, ok. It's worth commenting that we are returning TRANSLATE_PMP_FAIL
>as that will be translated to an access fault
Ack.
>
>Alistair
>
>>
>> >
>> >Alistair
next prev parent reply other threads:[~2024-08-29 0:17 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-08-28 17:47 [PATCH v11 00/20] riscv support for control flow integrity extensions Deepak Gupta
2024-08-28 17:47 ` [PATCH v11 01/20] target/riscv: expose *envcfg csr and priv to qemu-user as well Deepak Gupta
2024-08-28 17:47 ` [PATCH v11 02/20] target/riscv: Add zicfilp extension Deepak Gupta
2024-08-28 17:47 ` [PATCH v11 03/20] target/riscv: Introduce elp state and enabling controls for zicfilp Deepak Gupta
2024-08-28 17:47 ` [PATCH v11 04/20] target/riscv: save and restore elp state on priv transitions Deepak Gupta
2024-08-28 17:47 ` [PATCH v11 05/20] target/riscv: additional code information for sw check Deepak Gupta
2024-08-28 17:47 ` [PATCH v11 06/20] target/riscv: tracking indirect branches (fcfi) for zicfilp Deepak Gupta
2024-08-28 17:47 ` [PATCH v11 07/20] target/riscv: zicfilp `lpad` impl and branch tracking Deepak Gupta
2024-08-28 17:47 ` [PATCH v11 08/20] disas/riscv: enable `lpad` disassembly Deepak Gupta
2024-08-28 17:47 ` [PATCH v11 09/20] target/riscv: Expose zicfilp extension as a cpu property Deepak Gupta
2024-08-28 17:47 ` [PATCH v11 10/20] target/riscv: Add zicfiss extension Deepak Gupta
2024-08-28 17:47 ` [PATCH v11 11/20] target/riscv: introduce ssp and enabling controls for zicfiss Deepak Gupta
2024-08-28 23:16 ` Alistair Francis
2024-08-28 17:47 ` [PATCH v11 12/20] target/riscv: tb flag for shadow stack instructions Deepak Gupta
2024-08-29 1:34 ` Richard Henderson
2024-08-28 17:47 ` [PATCH v11 13/20] target/riscv: mmu changes for zicfiss shadow stack protection Deepak Gupta
2024-08-28 23:29 ` Alistair Francis
2024-08-28 23:45 ` Deepak Gupta
2024-08-29 0:03 ` Alistair Francis
2024-08-29 0:17 ` Deepak Gupta [this message]
2024-08-28 17:47 ` [PATCH v11 14/20] target/riscv: AMO operations always raise store/AMO fault Deepak Gupta
2024-08-28 23:33 ` Alistair Francis
2024-08-28 17:47 ` [PATCH v11 15/20] target/riscv: update `decode_save_opc` to store extra word2 Deepak Gupta
2024-08-28 23:36 ` Alistair Francis
2024-08-28 17:47 ` [PATCH v11 16/20] target/riscv: implement zicfiss instructions Deepak Gupta
2024-08-29 0:01 ` Alistair Francis
2024-08-29 0:06 ` Deepak Gupta
2024-08-29 0:07 ` Alistair Francis
2024-08-29 0:15 ` Deepak Gupta
2024-08-28 17:47 ` [PATCH v11 17/20] target/riscv: compressed encodings for sspush and sspopchk Deepak Gupta
2024-08-29 0:03 ` Alistair Francis
2024-08-28 17:47 ` [PATCH v11 18/20] disas/riscv: enable disassembly for zicfiss instructions Deepak Gupta
2024-08-29 0:04 ` Alistair Francis
2024-08-28 17:47 ` [PATCH v11 19/20] disas/riscv: enable disassembly for compressed sspush/sspopchk Deepak Gupta
2024-08-29 0:06 ` Alistair Francis
2024-08-28 17:47 ` [PATCH v11 20/20] target/riscv: Expose zicfiss extension as a cpu property Deepak Gupta
2024-08-29 0:06 ` Alistair Francis
2024-08-28 17:50 ` [PATCH v11 00/20] riscv support for control flow integrity extensions Deepak Gupta
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