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Tue, 4 Aug 2026 05:57:25 +0000 (GMT) Message-ID: <8eda9bd3-d58c-41a0-a144-d02cb7d72a25@linux.ibm.com> Date: Tue, 4 Aug 2026 11:27:24 +0530 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 2/5] powerpc/pseries: Add RTAS error injection buffer infrastructure To: Sourabh Jain , mahesh@linux.ibm.com, maddy@linux.ibm.com, mpe@ellerman.id.au, christophe.leroy@csgroup.eu, gregkh@linuxfoundation.org, oohall@gmail.com, npiggin@gmail.com Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, tyreld@linux.ibm.com, vaibhav@linux.ibm.com, sbhat@linux.ibm.com, ganeshgr@linux.ibm.com, haren@linux.ibm.com, thuth@redhat.com References: <20260527072433.94510-1-nnmlinux@linux.ibm.com> <20260527072433.94510-3-nnmlinux@linux.ibm.com> Content-Language: en-US From: Narayana Murty N In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-Reinject: loops=2 maxloops=12 X-Proofpoint-GUID: D9HToVF_HFE1Z1RK-oo1qMlEKhMq7Q68 X-Proofpoint-ORIG-GUID: qxQistu2AmU2xwMhKcaCg_2lVltndpCs X-Proofpoint-Spam-Info: AW1haW4tMjYwODA0MDA0MyBTYWx0ZWRfX1GZbKa+n0G7m XsPU1q52ocdkUN/UNGTfc5r3vWttWj1ra9Q76/+Txe3pCom90g73VJhH9ZS6kGLKKNZ05RJwkRZ 9U0wnjTv3THbkDeEsK5AboNyZY847kw= X-Authority-Analysis: v=2.4 cv=K8cS2SWI c=1 sm=1 tr=0 ts=6a717f50 cx=c_pps a=3Bg1Hr4SwmMryq2xdFQyZA==:117 a=3Bg1Hr4SwmMryq2xdFQyZA==:17 a=IkcTkHD0fZMA:10 a=Sv0fKeRqtYgA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=uAbxVGIbfxUO_5tXvNgY:22 a=VwQbUJbxAAAA:8 a=VnNF1IyMAAAA:8 a=YnlHx7dLygz1jVq2heAA:9 a=3ZKOabzyN94A:10 a=QEXdDO2ut3YA:10 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwODA0MDA0MyBTYWx0ZWRfX/+yhLcOJ+FnW 3BXjibOFwfG8MieAZyB/jiZym9R3N+ZeZvTJj0wiotpDOwAbM7w5CXo3ZJKP0lXytkPXUfosM+b k0D3KKIQMuuqpGAHg5wuh9u+18C6D1Z1NQk3SXCsHu0kOA34lc2FENWEZAOrg3FtWk48FyaT86/ CeFIcIF4839IYD8AfB0nxYDgVCXssnUR1zH857LTG164zuV6FkCV8h3L3Isurk9Zaxxsr07fyL2 nhyz+MfRou20QX3xHv3wB0AA3qOoA2ezRlG4PHQu4LAPSZzfcV4EwPSp2H52BDdQD5b7f8WzxcM QpJGHXQ1LzI6AU/nXJUhsFG7DQUhAxe9wvuTxE69B1BvSfbbF4e28wS71mwfrC3d+rzZd87BgTU 6y11El7ARreZGMbetV+rTaXjBpVZUWLgGLnjBPpsLUnR+ba9nc+J1jtXYy2VIo/6OALO/pvZSog ulDX+T2aH8dA0aTqU6Q== X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1176,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-08-04_01,2026-08-03_02,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 clxscore=1015 spamscore=0 impostorscore=0 bulkscore=0 priorityscore=1501 lowpriorityscore=0 malwarescore=0 phishscore=0 suspectscore=0 adultscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2608040043 On 10/06/26 8:57 AM, Sourabh Jain wrote: > > > On 27/05/26 12:54, Narayana Murty N wrote: >> Adds global infrastructure required by the injection engine: >>   - a 1KB aligned RTAS working buffer in rtas.c >>   - a spinlock to serialize buffer access >>   - UAPI definitions for error-injection tokens (added to eeh.h) >> >> Signed-off-by: Narayana Murty N >> --- >>   arch/powerpc/include/asm/rtas.h     | 21 +++++++++++++++++++++ >>   arch/powerpc/include/uapi/asm/eeh.h | 18 ++++++++++++++++++ >>   arch/powerpc/kernel/rtas.c          | 12 ++++++++++++ >>   3 files changed, 51 insertions(+) >> >> diff --git a/arch/powerpc/include/asm/rtas.h >> b/arch/powerpc/include/asm/rtas.h >> index d046bbd5017d..82512f822c7a 100644 >> --- a/arch/powerpc/include/asm/rtas.h >> +++ b/arch/powerpc/include/asm/rtas.h >> @@ -519,6 +519,27 @@ int rtas_get_error_log_max(void); >>   extern spinlock_t rtas_data_buf_lock; >>   extern char rtas_data_buf[RTAS_DATA_BUF_SIZE]; >>   +/* >> + * RTAS Error Injection Buffer (PAPR-compliant) >> + * ============================================ >> + * >> + * 1KB aligned, zero-initialized buffer for ibm,errinjct RTAS work >> area. >> + * Protected by rtas_errinjct_buf_lock for concurrent access safety. >> + * >> + * PAPR Requirement: ibm,errinjct requires a caller-allocated buffer >> passed >> + * via physical address. Buffer must accommodate largest error type >> layouts: >> + * - IOA bus error (64-bit): 8x32-bit words (32 bytes) >> + * - All other types: <=4x32-bit words (16 bytes) >> + * >> + * Usage: >> + * prepare_errinjct_buffer() -> spin_lock() -> rtas_call() -> >> spin_unlock() >> + * >> + * Alignment: SZ_1K ensures PAPR firmware requirements and >> cache-line safety. >> + */ >> +#define RTAS_ERRINJCT_BUF_SIZE 1024 >> +extern spinlock_t rtas_errinjct_buf_lock; >> +extern char rtas_errinjct_buf[RTAS_ERRINJCT_BUF_SIZE]; > > The kernel has a similar buffer for userspace (named rtas_rmo_buf), > which is allocated in the range (0, min(ppc64_rma_size, > RTAS_INSTANTIATE_MAX)). > > Whereas, the base address of the statically allocated > rtas_errinjct_buf array > depends on the location at which the kernel is loaded, which could be > higher than > RTAS_INSTANTIATE_MAX. > > Also, things will break if the base address of rtas_errinjct_buf is > greater than > 4 GB. In that case, the kernel will send a truncated address, and RTAS > may > corrupt memory as a result. > > Why don't we allocate rtas_errinjct_buf in the same range where > rtas_rmo_buf is allocated? Yes, I do agree for the design direction and is addressed in V3 patch https://lore.kernel.org/all/20260721033815.5300-1-nnmlinux@linux.ibm.com/ >> + >>   /* RMO buffer reserved for user-space RTAS use */ >>   extern unsigned long rtas_rmo_buf; >>   diff --git a/arch/powerpc/include/uapi/asm/eeh.h >> b/arch/powerpc/include/uapi/asm/eeh.h >> index 3b5c47ff3fc4..86645cab2827 100644 >> --- a/arch/powerpc/include/uapi/asm/eeh.h >> +++ b/arch/powerpc/include/uapi/asm/eeh.h >> @@ -41,4 +41,22 @@ >>   #define EEH_ERR_FUNC_DMA_WR_TARGET    19 >>   #define EEH_ERR_FUNC_MAX        19 >>   +/* RTAS PCI Error Injection Token Types */ >> +#define RTAS_ERR_TYPE_FATAL                     0x1 >> +#define RTAS_ERR_TYPE_RECOVERED_RANDOM_EVENT    0x2 >> +#define RTAS_ERR_TYPE_RECOVERED_SPECIAL_EVENT   0x3 >> +#define RTAS_ERR_TYPE_CORRUPTED_PAGE            0x4 >> +#define RTAS_ERR_TYPE_CORRUPTED_SLB             0x5 >> +#define RTAS_ERR_TYPE_TRANSLATOR_FAILURE        0x6 >> +#define RTAS_ERR_TYPE_IOA_BUS_ERROR             0x7 >> +#define RTAS_ERR_TYPE_PLATFORM_SPECIFIC         0x8 >> +#define RTAS_ERR_TYPE_CORRUPTED_DCACHE_START    0x9 >> +#define RTAS_ERR_TYPE_CORRUPTED_DCACHE_END      0xA >> +#define RTAS_ERR_TYPE_CORRUPTED_ICACHE_START    0xB >> +#define RTAS_ERR_TYPE_CORRUPTED_ICACHE_END      0xC >> +#define RTAS_ERR_TYPE_CORRUPTED_TLB_START       0xD >> +#define RTAS_ERR_TYPE_CORRUPTED_TLB_END         0xE >> +#define RTAS_ERR_TYPE_IOA_BUS_ERROR_64          0xF >> +#define RTAS_ERR_TYPE_UPSTREAM_IO_ERROR         0x10 >> + >>   #endif /* _ASM_POWERPC_EEH_H */ >> diff --git a/arch/powerpc/kernel/rtas.c b/arch/powerpc/kernel/rtas.c >> index a2dd94eed9d0..c110965ea1d9 100644 >> --- a/arch/powerpc/kernel/rtas.c >> +++ b/arch/powerpc/kernel/rtas.c >> @@ -769,6 +769,18 @@ EXPORT_SYMBOL_GPL(rtas_data_buf); >>     unsigned long rtas_rmo_buf; >>   +/* >> + * RTAS Error Injection Buffer - Global Definitions >> + * Global 1KB buffer and spinlock for ibm,errinjct RTAS service. >> + * Exported for pseries EEH error injection usage. >> + */ >> + >> +DEFINE_SPINLOCK(rtas_errinjct_buf_lock); >> +EXPORT_SYMBOL_GPL(rtas_errinjct_buf_lock); >> + >> +char rtas_errinjct_buf[1024] __aligned(SZ_1K); >> +EXPORT_SYMBOL_GPL(rtas_errinjct_buf); >> + >>   /* >>    * If non-NULL, this gets called when the kernel terminates. >>    * This is done like this so rtas_flash can be a module. > Thanks, Narayana