From mboxrd@z Thu Jan 1 00:00:00 1970 From: Zoltan Menyhart Date: Thu, 28 Feb 2008 09:11:53 +0000 Subject: ia64_mca_cpe_int_handler - take 3 Message-Id: <47C67AD9.9030404@bull.net> MIME-Version: 1 Content-Type: multipart/mixed; boundary="------------070103060507050906020505" List-Id: To: linux-ia64@vger.kernel.org This is a multi-part message in MIME format. --------------070103060507050906020505 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit The ia64_mca_cpe_int_handler() and the ia64_mca_cmc_int_handler() are not safe against nested interrupts. The interrupts are enabled too early. The interrupts should remain blocked while we are inside the lock- protected region. (See ..._history_lock.) The interrupts will be enabled in ia64_mca_log_sal_error_record() unless it is called from the MCA/INIT handlers. Please have a look at this patch. Thanks, Zoltan Menyhart Signed-off-by: Zoltan Menyhart, --------------070103060507050906020505 Content-Type: text/plain; name="mca.c-patch-new" Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="mca.c-patch-new" --- linux-2.6.24-old/arch/ia64/kernel/mca.c 2008-02-28 09:32:09.000000000 +0100 +++ linux-2.6.24/arch/ia64/kernel/mca.c 2008-02-28 09:32:09.000000000 +0100 @@ -176,6 +176,14 @@ oops_in_progress = 0; /* + * It is not safe enabling interrupts (nor touching locks) in + * MCA/INIT handler context. + */ +#define MCA_IRQ_NOTSAFE 0 /* Called from the MCA/INIT handlers */ +#define MCA_IRQ_SAFE 1 /* NOT called from the MCA/INIT handlers */ + + +/* * Push messages into buffer, print them later if not urgent. */ void ia64_mca_printk(const char *fmt, ...) @@ -423,19 +431,26 @@ * and wakes up any processes waiting for error records. * * Inputs : sal_info_type (Type of error record MCA/CMC/CPE) - * FIXME: remove MCA and irq_safe. + * irq_safe (MCA_IRQ_NOTSAFE == 0 if called from the MCA/INIT handlers, + * MCA_IRQ_SAFE == 1 otherwise) */ static void -ia64_mca_log_sal_error_record(int sal_info_type) +ia64_mca_log_sal_error_record(int sal_info_type, int irq_safe) { u8 *buffer; sal_log_record_header_t *rh; u64 size; - int irq_safe = sal_info_type != SAL_INFO_TYPE_MCA; #ifdef IA64_MCA_DEBUG_INFO static const char * const rec_name[] = { "MCA", "INIT", "CMC", "CPE" }; #endif + if (irq_safe){ + /* SAL spec says: SAL_GET_STATE_INFO() and SAL_CLEAR_STATE_INFO() + * should be called with interrupts enabled, unless we are in + * MCA/INIT handlers. + */ + local_irq_enable(); + } size = ia64_log_get(sal_info_type, &buffer, irq_safe); if (!size) return; @@ -512,9 +527,6 @@ IA64_MCA_DEBUG("%s: received interrupt vector = %#x on CPU %d\n", __FUNCTION__, cpe_irq, smp_processor_id()); - /* SAL spec states this should run w/ interrupts enabled */ - local_irq_enable(); - spin_lock(&cpe_history_lock); if (!cpe_poll_enabled && cpe_vector >= 0) { @@ -553,7 +565,7 @@ spin_unlock(&cpe_history_lock); out: /* Get the CPE error record and log it */ - ia64_mca_log_sal_error_record(SAL_INFO_TYPE_CPE); + ia64_mca_log_sal_error_record(SAL_INFO_TYPE_CPE, MCA_IRQ_SAFE); return IRQ_HANDLED; } @@ -1245,7 +1257,7 @@ } /* Get the MCA error record and log it */ - ia64_mca_log_sal_error_record(SAL_INFO_TYPE_MCA); + ia64_mca_log_sal_error_record(SAL_INFO_TYPE_MCA, MCA_IRQ_NOTSAFE); /* MCA error recovery */ recover = (ia64_mca_ucmc_extension @@ -1322,9 +1334,6 @@ IA64_MCA_DEBUG("%s: received interrupt vector = %#x on CPU %d\n", __FUNCTION__, cmc_irq, smp_processor_id()); - /* SAL spec states this should run w/ interrupts enabled */ - local_irq_enable(); - spin_lock(&cmc_history_lock); if (!cmc_polling_enabled) { int i, count = 1; /* we know 1 happened now */ @@ -1367,7 +1376,7 @@ spin_unlock(&cmc_history_lock); out: /* Get the CMC error record and log it */ - ia64_mca_log_sal_error_record(SAL_INFO_TYPE_CMC); + ia64_mca_log_sal_error_record(SAL_INFO_TYPE_CMC, MCA_IRQ_SAFE); return IRQ_HANDLED; } --------------070103060507050906020505--