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Some register blocks of the ast2500 are protected by protection key registers which require the right magic value to be written to those registers to allow those registers to be mutated. Register manuals indicate that writing the correct magic value to these registers should cause subsequent reads from those values to return 1, and writing any other value should cause subsequent reads to return 0. Previously, qemu implemented these registers incorrectly: the registers were handled as simple memory, meaning that writing some value x to a protection key register would result in subsequent reads from that register returning the same value x. The protection was implemented by ensuring that the current value of that register equaled the magic value. This modifies qemu to have the correct behaviour: attempts to write to a ast2500 protection register results in a transition to 1 or 0 depending on whether the written value is the correct magic. The protection logic is updated to ensure that the value of the register is nonzero. This bug caused deadlocks with u-boot HEAD: when u-boot is done with a protectable register block, it attempts to lock it by writing the bitwise inverse of the correct magic value, and then spinning forever until the register reads as zero. Since qemu implemented writes to these registers as ordinary memory writes, writing the inverse of the magic value resulted in subsequent reads returning that value, leading to u-boot spinning forever. Signed-off-by: Hugo Landau <hlandau@devever.net> Reviewed-by: Cédric Le Goater <clg@kaod.org> Acked-by: Andrew Jeffery <andrew@aj.id.au> Message-id: 20180220132627.4163-1-hlandau@devever.net [PMM: fixed incorrect code indentation] Signed-off-by: Peter Maydell <peter.maydell@linaro.org> |
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| .. | ||
| macio | ||
| a9scu.c | ||
| applesmc.c | ||
| arm11scu.c | ||
| arm_integrator_debug.c | ||
| arm_l2x0.c | ||
| arm_sysctl.c | ||
| aspeed_scu.c | ||
| aspeed_sdmc.c | ||
| auxbus.c | ||
| bcm2835_mbox.c | ||
| bcm2835_property.c | ||
| bcm2835_rng.c | ||
| cbus.c | ||
| debugexit.c | ||
| eccmemctl.c | ||
| edu.c | ||
| exynos4210_clk.c | ||
| exynos4210_pmu.c | ||
| exynos4210_rng.c | ||
| hyperv_testdev.c | ||
| imx2_wdt.c | ||
| imx6_ccm.c | ||
| imx6_src.c | ||
| imx7_ccm.c | ||
| imx7_gpr.c | ||
| imx7_snvs.c | ||
| imx25_ccm.c | ||
| imx31_ccm.c | ||
| imx_ccm.c | ||
| ivshmem.c | ||
| Makefile.objs | ||
| max111x.c | ||
| milkymist-hpdmc.c | ||
| milkymist-pfpu.c | ||
| mips_cmgcr.c | ||
| mips_cpc.c | ||
| mips_itu.c | ||
| mmio_interface.c | ||
| mos6522.c | ||
| mps2-scc.c | ||
| msf2-sysreg.c | ||
| mst_fpga.c | ||
| omap_clk.c | ||
| omap_gpmc.c | ||
| omap_l4.c | ||
| omap_sdrc.c | ||
| omap_tap.c | ||
| pc-testdev.c | ||
| pci-testdev.c | ||
| puv3_pm.c | ||
| pvpanic.c | ||
| sga.c | ||
| slavio_misc.c | ||
| stm32f2xx_syscfg.c | ||
| tmp105.c | ||
| tmp105.h | ||
| tmp421.c | ||
| trace-events | ||
| unimp.c | ||
| vmcoreinfo.c | ||
| zynq_slcr.c | ||
| zynq-xadc.c | ||