From 69e7e60d011846f066af97589660eef52898519a Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Alex=20Benn=C3=A9e?= Date: Mon, 21 Nov 2022 11:45:13 +0000 Subject: [PATCH] hw/intc: clean-up access to GIC multi-byte registers MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit gic_dist_readb was returning a word value which just happened to work as a result of the way we OR the data together. Lets fix it so only the explicit byte is returned for each part of GICD_TYPER. I've changed the return type to uint8_t although the overflow is only detected with an explicit -Wconversion. Signed-off-by: Alex Bennée Signed-off-by: Peter Maydell Reviewed-by: Philippe Mathieu-Daudé Reviewed-by: Peter Maydell Signed-off-by: Peter Maydell --- hw/intc/arm_gic.c | 16 ++++++++++------ 1 file changed, 10 insertions(+), 6 deletions(-) diff --git a/hw/intc/arm_gic.c b/hw/intc/arm_gic.c index 492b2421ab..1a04144c38 100644 --- a/hw/intc/arm_gic.c +++ b/hw/intc/arm_gic.c @@ -941,7 +941,7 @@ static void gic_complete_irq(GICState *s, int cpu, int irq, MemTxAttrs attrs) gic_update(s); } -static uint32_t gic_dist_readb(void *opaque, hwaddr offset, MemTxAttrs attrs) +static uint8_t gic_dist_readb(void *opaque, hwaddr offset, MemTxAttrs attrs) { GICState *s = (GICState *)opaque; uint32_t res; @@ -955,6 +955,7 @@ static uint32_t gic_dist_readb(void *opaque, hwaddr offset, MemTxAttrs attrs) cm = 1 << cpu; if (offset < 0x100) { if (offset == 0) { /* GICD_CTLR */ + /* We rely here on the only non-zero bits being in byte 0 */ if (s->security_extn && !attrs.secure) { /* The NS bank of this register is just an alias of the * EnableGrp1 bit in the S bank version. @@ -964,11 +965,14 @@ static uint32_t gic_dist_readb(void *opaque, hwaddr offset, MemTxAttrs attrs) return s->ctlr; } } - if (offset == 4) - /* Interrupt Controller Type Register */ - return ((s->num_irq / 32) - 1) - | ((s->num_cpu - 1) << 5) - | (s->security_extn << 10); + if (offset == 4) { + /* GICD_TYPER byte 0 */ + return ((s->num_irq / 32) - 1) | ((s->num_cpu - 1) << 5); + } + if (offset == 5) { + /* GICD_TYPER byte 1 */ + return (s->security_extn << 2); + } if (offset < 0x08) return 0; if (offset >= 0x80) {